when to cite a source in a research paper

Professor Receives $3.8M NIH Grant to Study Impact of Medicaid ACOs on Maternal Health Outcomes

when to cite a source in a research paper

Pregnancy-related Deaths Spiked for Second Consecutive Year during COVID-19

When to cite ..

Now that you have consulted the literature and are ready to synthesize your information, be careful to adequately give credit to original authors by citing appropriately.  This is a critical skill that all public health professionals must develop. The general convention is: “ when in doubt, cite ” (1). There is no such thing as “over-citing,” so cite the original source as much as possible.

You must cite the source every time you incorporate research, words, ideas, data, or information that is not your own (2). While you are synthesizing and often summarizing many pieces of information, you must cite any concept that is not your own. This includes any source that contributes, either directly or indirectly, to your knowledge and understanding of the material and the formulation of your arguments (3).

Here are five basic principles to guide in you in the citing process:

When NOT to Cite

It is best practice to cite whenever possible. However, there are certain instances in which citing may not be necessary. Below are some examples in which you may not need to cite. However, if you are in doubt, it is best to cite the source and consult your instructor.

when to cite a source in a research paper

Featured Story

Writing is hard. the public health writing program is here to help, additional resources.

For more information on avoiding plagiarism, visit the Understanding Plagiarism section of the Writing Guide and check out the  SPH Plagiarism Tutorial . You may also wish to check out these resources:

Learn more about BUSPH Public Health Writing

Search form

You are here

Warning: when you must cite.

Although you should use sources creatively and flexibly to help you generate ideas and sharpen your argument, there are some hard-and-fast rules about the way sources should be acknowledged in your project. Click on the links for more explanation of the various rules.

ALWAYS CITE, in the following cases:

1. When you quote two or more words verbatim, or even one word if it is used in a way that is unique to the source.

Most writers realize that they must acknowledge a source when quoting a memorable phrase or sentence. They’d be sure to credit Mark Twain when quoting: “The coldest winter I ever spent was a summer in San Francisco.” And you probably also understand that you do not need to cite words that are very common to your topic. When writing about Hamlet, you do not need to put the words “Hamlet” or “Shakespeare” in quotation marks, or cite a source for them, even though you may have read sources that use these words. But when a single word or two are used in a distinctive way, so that the author is creating a new concept or applying it to a new topic, you must give acknowledge the source. When John Baker redefines the significance of the mirror test by saying that chimpanzees’ awareness of their reflection is not full consciousness, but a limited “kinesthetic self-concept,” it’s clear that those two words, as specialized terms of art, should appear in quotation marks in your paper. Even though neither “kinesthetic” nor “self-concept” is unusual on its own, as a phrase they belong to the author. But even a single, non-specialist term—such as “consilience”—may become tied to an author (in this case, E.O. Wilson) through an influential publication, in which case you should put the single word in quotation marks, at least in your first mention of it in your text.

2. When you introduce facts that you have found in a source.

Facts that are generally accessible (the date of the Declaration of Independence, for instance) need not be cited to a particular source, but once you go up one level of detail on the information ladder, you probably need to cite the source (the number of people who signed the Declaration, for instance). And note that commonly known facts found in a particular or unusual context should be cited, so that the reader knows how your argument may have been influenced by the context in which you found it. For more, see Common Knowledge .

3. When you paraphrase or summarize ideas, interpretations, or conclusions that you find in a source. For more explanation, see Fair Paraphrase .

4. when you introduce information that is not common knowledge or that may be considered common knowledge in your field, but the reader may not know it. for more information, see common knowledge ., 5. when you borrow the plan or structure of a larger section of a source’s argument (for example, using a theory from a source and analyzing the same three case studies that the source uses)..

You may not be used to thinking of the plan of a source as proprietary to its author, but if you follow a source’s plan too closely without acknowledging that you saw it there first, you’re presenting as your own an analysis that someone else shaped. For example, if use Mark Hauser’s discussion of primates’ knowledge of other minds from Wild Minds and you discuss the same three experiments that he analyzes, then you must acknowledge this debt. The simplest way to do this is to say “Like Mark Hauser, I find the three experiments carried out by X, Y, and Z groups to be useful in considering the extent of chimpanzee awareness.” An even better way—because it highlights your distinctiveness as a writer—is to distinguish the different use to which you will put the analysis. If, for instance, you’re focusing on primate social skills rather than strictly on their awareness of other minds, you might write: “Mark Hauser examines three experiments carried out by X, Y, and Z for what they can tell us about knowledge of other minds. For my purposes, though, these same experiments shed important light on the social capacities of primates.” These statements can come in a discursive footnote or in the main body, although if the statement distinguishes your argument from the source’s, it has an important role in the body of the argument.

See Gordon Harvey, Writing With Sources , Chapter 3, for an excellent discussion of unfair borrowing of another’s plan.

6. When you build on another’s method found either in a source or from collaborative work in a lab.

Relying on someone’s research method is like #5 above—borrowing a text’s plan or structure. If your approach to a problem is inspired by someone else’s work on a similar or analogous case, credit the original researcher. Building on the work of others is appropriate and desirable, but methods, like specific words and phrases, are a form of intellectual property.

7. When you build on another’s program or on a not-commonly-known algorithm in writing computer code.

Although writing code may seem different from writing papers, the same standards of acknowledgment apply. If you rely on someone else’s program, you must credit that person. Some software algorithms are so well known that they rise to the level of Common Knowledge . Programmers use such pieces of code without acknowledgement. But if the code is not well known, someone reading your program might think you’ve authored parts that are borrowed. For a useful example of unauthorized code borrowing, see this page of the Princeton University website .

8. When you collaborate with others in producing knowledge.

You may sometimes co-author a paper or other text during college; these opportunities are often more frequent in the professional world. When two or more people all contribute substantially to a piece, they normally list all their names as authors. But there are also occasions when someone gives help that does not rise to the level of co-authorship. If you work with a lab partner to set up an experiment, for instance, but run and analyze the results yourself, you should credit the lab partner in a footnote or by reference within your paper. Similarly, if you and a partner present a scene from a play, and you later write a paper using some of the insights you gained during production, you should credit the other actor.

University life is structured so that your ideas will receive constant testing and refinement in discussion with others. You do not need to cite in your papers every conversation you have about the ideas or evidence. But you do need to develop a judgment about which conversations are incidental and which result in ideas that merit reference in your texts. If you take this warning as an opportunity, and make an effort to reveal the trail of your thinking in footnotes and acknowledgements, you’ll soon develop a sense of how to credit collaboration appropriately.


Students Studying in Sterling Memorial Library

Study Halls & Workshops

A quiet space to write in the company of other writers, with Writing Partners on hand to answer questions and snacks to fuel your work.

when to cite a source in a research paper

Reserve a Room

The Poorvu Center for Teaching and Learning partners with departments and groups on-campus throughout the year to share its space. Please review the reservation form and submit a request.

when to cite a source in a research paper

Writing Handouts

Principles, strategies, and models to deepen your understanding of what good writing looks like—and how to achieve it.

University Library

Start your research.

Cite your sources

What is a Citation?

A citation identifies for the reader the original source for an idea, information, or image that is referred to in a work.

Citation basics

From:  Lemieux  Library,  University  of Seattle 

Why Should You Cite?

Quoting Are you quoting two or more consecutive words from a source? Then the original source should be cited and the words or phrase placed in quotes. 

Paraphrasing If an idea or information comes from another source,  even if you put it in your own words , you still need to credit the source.  General vs. Unfamiliar Knowledge You do not need to cite material which is accepted common knowledge. If in doubt whether your information is common knowledge or not, cite it. Formats We usually think of books and articles. However, if you use material from web sites, films, music, graphs, tables, etc. you'll also need to cite these as well.

Plagiarism is presenting the words or ideas of someone else as your own without proper acknowledgment of the source. When you work on a research paper and use supporting material from works by others, it's okay to quote people and use their ideas, but you do need to correctly credit them. Even when you summarize or paraphrase information found in books, articles, or Web pages, you must acknowledge the original author.

Citation Style Help

Helpful links:

For additional writing resources specific to styles listed here visit the  Purdue OWL Writing Lab

Citation and Bibliography Resources

Writing an annotated bibliography

spacer bullet

Creative Commons Attribution 3.0 License except where otherwise noted.

Library Twitter page

Land Acknowledgement

The land on which we gather is the unceded territory of the Awaswas-speaking Uypi Tribe. The Amah Mutsun Tribal Band, comprised of the descendants of indigenous people taken to missions Santa Cruz and San Juan Bautista during Spanish colonization of the Central Coast, is today working hard to restore traditional stewardship practices on these lands and heal from historical trauma.

The land acknowledgement used at UC Santa Cruz was developed in partnership with the Amah Mutsun Tribal Band Chairman and the Amah Mutsun Relearning Program at the UCSC Arboretum .

Want to create or adapt books like this? Learn more about how Pressbooks supports open publishing practices.

8-How to Cite Sources

When to Cite

Citing sources is often described as a straightforward, rule-based practice. But in fact, there are many gray areas around citation, and learning how to apply citation guidelines takes practice and education. If you are confused by it, you are not alone – in fact you might be doing some good thinking. Here are some guidelines to help you navigate citation practices.

Cite when you are directly quoting. This is the easiest rule to understand. If you are stating word-for-word what someone else has already written, you must put quotes around those words and you must give credit to the original author. Not doing so would mean that you are letting your reader believe these words are your own and represent your own effort.

Cite when you are summarizing and paraphrasing. This is a trickier area to understand. First of all, summarizing and paraphrasing are two related practices but they are not the same. Summarizing is when you read a text, consider the main points, and provide a shorter version of what you learned. Paraphrasing is when you restate what the original author said in your own words and in your own tone. Both summarizing and paraphrasing require good writing skills and an accurate understanding of the material you are trying to convey. Summarizing and paraphrasing are difficult to do when you are a beginning academic researcher, but these skills become easier to perform over time with practice.

Cite when you are citing something that is highly debatable. For example, if you want to claim that the Patriot Act has been an important tool for national security, you should be prepared to give examples of how it has helped and how experts have claimed that it has helped. Many U.S. citizens concerned that it violates privacy rights won’t agree with you, and they will be able to find commentary that the Patriot Act has been more harmful to the nation than helpful. You need to be prepared to show such skeptics that you have experts on your side, too.

Tip: Why Cite Sources?

This section covers how and when to cite sources. For a discussion of why to cite sources, see Ethical Use of Sources .

When Don’t You Cite?

Don’t cite when what you are saying is your own insight. As you learned in  The Purpose of Academic Argument , research involves forming opinions and insights around what you learn. You may be citing several sources that have helped you learn, but at some point you must integrate your own opinion, conclusion, or insight into the work. The fact that you are not citing it helps the reader understand that this portion of the work is your unique contribution developed through your own research efforts.

Don’t cite when you are stating common knowledge. What is common knowledge is sometimes difficult to discern. In general, quick facts like historical dates or events are not cited because they are common knowledge.

Examples of information that would not need to be cited include:

Some quick facts, such as statistics, are trickier. For example, the number of gun-related deaths per year probably should be cited, because there are a lot of ways this number could be determined (does the number include murder only, or suicides and accidents, as well?) and there might be different numbers provided by different organizations, each with an agenda about gun laws.

A guideline that can help with deciding whether or not to cite facts is to determine whether the same data is repeated in multiple sources. If it is not, it is best to cite.

The other thing that makes this determination difficult might be that what seems new and insightful to you might be common knowledge to an expert in the field. You have to use your best judgment, and probably err on the side of over-citing, as you are learning to do academic research. You can seek the advice of your instructor, a writing tutor, or a librarian. Knowing what is and is not common knowledge is a practiced skill that gets easier with time and with your own increased knowledge.

Wikipedia Logo

Tip: Why You Can’t Cite Wikipedia

You’ve likely been told at some point that you can’t cite Wikipedia, or any encyclopedia for that matter, in your scholarly work.

The reason is that such entries are meant to prepare you to do research, not be evidence of your having done it. Wikipedia entries, which are tertiary sources, are already a summary of what is known about the topic. Someone else has already done the labor of synthesizing lots of information into a concise and quick way of learning about the topic.

So while Wikipedia is a great shortcut for getting context, background, and a quick lesson on topics that might not be familiar to you, don’t quote, paraphrase, or summarize from it. Just use it to educate yourself.

Activity: To Cite or Not to Cite?

Open activity in a web browser.

Choosing & Using Sources: A Guide to Academic Research by Teaching & Learning, Ohio State University Libraries is licensed under a Creative Commons Attribution 4.0 International License , except where otherwise noted.

Share This Book

Search for books, articles, media and more

Check the current status of our systems, applications, and online resources

Search the Library Website

Looking for a book, article, database or something else for your research, what is plagiarism.

Plagiarism is defined as "a piece of writing that has been copied from someone else and is presented as being your own work" or "taking someone's words or ideas as if they were your own"  [ 1 ]

Plagiarism is a serious issue in the academic community. While plagiarism sometimes does occur intentionally, it also occurs because the writer doesn’t understand or does not know how to avoid it. Please visit our online tutorial:  Plagiarism 101  for an entertaining and interesting look at why people plagiarize and strategies to avoid it.

Plagiarism occurs when you use someone else’s ideas and PRETEND they are your own. Avoiding plagiarism doesn’t mean that you can never use other people’s ideas. It’s a widely known secret that in fact you CAN use other peoples’ ideas and even their words. For many research papers you NEED to do this in order to prove your own points. So use their ideas! Use their words! Professors expect to see in your writing that you’ve done your research and understand what the experts think when you formed your own opinions. The trick is to acknowledge who these expert ideas really belong to by CITING them!

So let’s assume you don’t want to plagiarize, you’ve given yourself enough time to do it right, but you’re still not sure about “putting things in your own words,” judging when to cite work, or how to cite it. Read on for more information and examples.

Why acknowledge sources?

Doing research for a paper is an exploration and learning process. By acknowledging our sources we show our reader the path we took to come to our conclusions. Citing the authors we read shows how we tied others’ research and ideas together and how we came to learn about and develop our own ideas and opinions.

Why should you cite your sources?

1. Citations reflect the careful and thorough work you have put into locating and exploring your sources.

2. Citations help readers understand the context of your argument and are a courtesy to the reader, who may share your interest in a particular area of study.

3. Citations allow you to acknowledge those authors who contributed to your learning and your work.

4. Citations, by illustrating your own learning process, also draw attention to the originality and legitimacy of your own ideas.

5. By citing sources you demonstrate your integrity and skill as a responsible student and participant in your field of study.  [ 2 ]

When to cite sources

While professors and scholars may have specific requirements based on the needs of their discipline, there are cases where you should  always  cite your sources.

1. Direct quotes of more than one word.  If the author’s words are powerful or you need to be specific for your argument, the authors’ words can be used as a direct quote.

2. Paraphrasing or summarizing.  If you want to use someone else’s idea to help you make your point or to support your own ideas, in this case you would “translate” the ideas into your own words.

3. Information which may be common knowledge  but still unfamiliar to your reader. This would also include statistical information which may be familiar information but still requires confirmation.

4. Not just books or articles  should be cited. Any source that you use for information can and should be cited including interviews, websites, TV programs, etc.

5. Whenever you are not sure  if something should be cited, err on the side of caution and cite sources.

Let’s look at some examples…

Direct quotes

How much you quote will determine how it appears in the body of your paper but whether it is one word or an entire paragraph, direct quotes need to be cited.

Lappe’s explanation of a "thin democracy"  [ 3 ]  addresses a number of basic flaws within our American society.

Global warming is being recognized as a major issue throughout the world and as Al Gore instructs, "it is time to make peace with our planet."  [ 4 ]

Paraphrasing or Summarizing

This involves translating what you have read (or heard) and putting it into your own words. Paraphrasing typically refers to putting an idea or passage into your own words. Summarizing involves capturing the main idea or reducing a detailed piece to a shorter and more general synopsis.

Here's an example:

"Instructors usually allow students to find their own topics for a major writing assignment; thus choose something of interest to you so you won’t get bored after a few days. At the same time, your chosen topic will need a scholarly perspective." [ 5 ]

Paraphrase : When students are permitted to select their own topic to write about they should choose one that is interesting to them. The topic should also be scholarly in nature so that students will be able to find appropriate research and resources on the topic.  [ 5 ]

Summary : Students should select writing topics that are interesting and also lend themselves to academic research.  [ 5 ]

A summary generally addresses the overall theme of a passage, article, opinion, etc. while a paraphrase generally restates a more specific thought or idea. The difference between summarizing and paraphrasing is sometimes obvious and sometimes subtle — do you see the difference?

Common Knowledge? Or Not?

Some basic facts are common knowledge and easily confirmed from a variety of sources. Statistics should always be cited, as well as opinions and less familiar facts. Information that is considered well-known within your field of study will also help determine if it is considered common or not. However, if you are not sure, cite it!

The University at Albany located in Albany, New York and is part of the State University of New York.

This is common knowledge and easily confirmed in a multitude of sources.

The State University of New York was officially established in February of 1948 and currently consists of 64 institutions. The University at Albany is one of ten University Centers that are part of the SUNY system.  [ 6 ]

While the SUNY system is well known and these facts are easily confirmed, specific historical information or statistics should be cited.

How to cite?

We’ve talked about plagiarism as well as why and when to cite. The next question is "How?"

There are  two things you need to know  from your professor.

The FIRST is how you will reference your sources within your paper. Generally you will use one of the following options:

The SECOND thing you need to know is what Format and Style Guide to use. There are very specific rules about how to do this that are not included in this document. Your professor will tell you which s/he wants you to follow. The choices will typically be one of the following:

Please visit the University Libraries' Citation Basics research guide  for information and instructions on these style guides. Once you know what your professor wants you will need to follow the rules of that format accordingly.

[ 1 ]  "Plagiarism."  WordNet 3.0 . Princeton University. 03 Apr. 2008.  Dictionary.com http://dictionary.reference.com/browse/plagiarism .

[ 2 ] Adapted from "Sources and Citation at Dartmouth College." Dartmouth College. 1998. Retrieved 9 Feb 2009.  http://www.dartmouth.edu/~writing/sources/sources-citation.html

[ 3 ] Lappe, Frances Moore.  Getting a Grip.  Cambridge, MA : Small Planet Media, 2007.

[ 4 ] Gore, Al. "Nobel Prize Acceptance Speech."  Al’s Journal . December 10, 2007. Retrieved April 10, 2008  http://blog.algore.com/2007/12/nobel_prize_acceptance_speech.html

[ 5 ] Lester, James D. & James D. Lester Jr.  Writing Research Papers: A Complete Guide, 11th Ed.  New York: Pearson Education, 2005.

[ 6 ] "Short History of SUNY." The State University of New York. 2008. Retrieved April 25, 2008.  http://www.suny.edu/student/university_suny_history.cfm

Still Have Questions?


Citing Sources

Why Do We Cite Our Research?

Sources of information are cited in order to give the original authors/creators proper credit for their work and to document where an author heard or read the fact or idea that has been incorporated into a new work. The purpose of citations is to let the reader know where you obtained information so sources can easily be located and consulted.

Because knowledge is a cumulative process built on the research and writing of other researchers, your instructor needs to see the quality of the sources you used and how you developed your ideas.

 To get started and to see examples, select the citation style from the dropdown menu on the left.

What Information Should Be Cited and Why?

In general, you must document sources when you provide information that you ordinarily would not have known before conducting your research, and when you provide information that it cannot be assumed the reader knows. You must cite a reference when you:

While you are doing research and locating sources, be sure to document materials thoroughly, noting the author, title, publisher, place of publication, date, and page numbers of all sources used. For electronic materials, you should also note the DOI number (Digital Object Identifier) if available. Note the URL of any website you consult; depending on the source, you may need it for reference.

APA style no longer requires a database name for most references; MLA style still requires it as part of your citation. In either case, make a note of it in case you need to retrieve it at a later date.

Common Knowledge

Things that are common knowledge do not require citation. For example:

However, if someone draws an original conclusion from a common fact, then you must cite the source:

Also, common sayings or proverbs need not be cited:

Below is a famous saying you might recognize, but it's actually from a poem by Sir Walter Scott. If you read this in a book, of course, you would cite the book. If you already knew this expression, you should still give Sir Walter Scott credit for it because it has a distinct and identifiable origin.

Getting started

We understand that citing your sources can be a little confusing, but it doesn't have to be overwhelming. Before you start, ask yourself these questions:

1. What type of source am I trying to cite?

2. Where did I retrieve that source?

3. What citation style am I supposed to use for my assignment?

Once you've answered these questions, select the most appropriate option from either the  APA  or  MLA  dropdown menu on the left to see examples.

Remember, individual help is always available through the  Center for Academic Enhancement  or email a Holy Family librarian at [email protected]

UC Logo

Using Information Sources Ethically and Legally

When do I need to cite sources?

Does everything need to be cited, all you need to know about citing sources, get help from libraries and writing centers.

Always give credit where credit is due. If the words that you are including in your research belong to someone else, give credit. 

Here is  a brief list of what needs to be credited or documented :  

There are certain things that  do not need documentation or credit, including :  

(From Plagiarism FAQs - Purdue Writing Lab )

The following chart from the UT Arlington Library Acknowledging Sources tutorial will guide you in your decision:

What is common knowledge? This refers to facts well known by many people and verifiable in five or more sources. Examples:

If you have any doubts or questions, ask your professor or librarian. Err on the side of caution: when in doubt, cite!

The online guide  Citing Your Sources provides information on citation, style guides, citation tools, amd more.

Writing Centers

Schedule an appointment

AWC Tutor Feedback (submit a paper of six double-spaced pages or less and get  feedback from a tutor within 48 hours)

Email: [email protected]

Email: [email protected]

Submit your work (submit a paper of six double-spaced pages or less and get  feedback from a tutor within 24-48 hours)

Email: [email protected]

University of Cincinnati Libraries

PO Box 210033 Cincinnati, Ohio 45221-0033

Phone: 513-556-1424

Contact Us | Staff Directory

University of Cincinnati

Alerts | Clery and HEOA Notice | Notice of Non-Discrimination | eAccessibility Concern | Privacy Statement | Copyright Information

© 2021 University of Cincinnati

How To Cite a Research Paper: Citation Styles Guide

How To Cite a Research Paper: Citation Styles Guide

If you are looking for the best advice on how to write a research paper , the first thing you would find is to cite your sources. In academic research, it is standardized by many institutions. And, publication venues such as conferences and journals are somehow strict about their formats. Hence, it is best for students with PhD degrees and aspiring researchers to know how to cite a research paper and other sources in their works. Citing your sources properly is also important for many reasons. One of the most important ones is that you can easily establish to your reviewers and readers the context around and relevancy of your work.

But, creating a reference section for your paper or dissertation can be a tedious task. As such, this article should serve as your guide on how to reference a research paper in popular formats: APA, MLA, Chicago/Turabian, and the IEEE style. A list of digital tools that can make citation easier and a quick tutorial will also be provided. This way, you can concentrate more on the content of your paper rather than what many consider a cumbersome task.

How To Cite a Research Paper Table of Contents

The rationale behind citations, apa style citation guide, mla style citation guide, chicago/turabian style citation guide, ieee style citation guide.

The main reason for citing references properly is to avoid intellectual dishonesty (Bast & Samuels, 2008). Presenting ideas of other scholars without proper research paper citation goes against scientific ethics (Gross, 2016). While this is not the highest of ethical requirements, it is simply basic decency. This is because we humans have a strong sense of ownership, not just of our physical properties but also of our intellectual works and achievements. We have a strong drive to know who or where exactly pieces of information came from and how ideas develop. Thus it is important to know how to give reference in a research paper.

In research, this is very apparent in literature where scholars discuss and debate who first created a research methodology , an idea, or made a discovery (e.g., Newton versus Leibniz for calculus and Le Verrier versus Adams for Neptune).

A free plagiarism checker for students does not make the cut. You must properly reference a source even if you have reworded the idea you lifted from it. Properly referencing a source is not only important that the right people get the proper recognition for their ideas. It is also crucial to the whole research publication and consumption process for the following reasons:

Overall, referencing helps research communities place a work in its proper context to better judge its potential impact on its field.

There are many different fields and disciplines in the research world. And, they have different styles and standards for what proper referencing is. Rules also vary from the types of sources you cite, including but not limited to research papers, technical reports, books, patents, court cases, conference journals, conference papers,  podcasts, YouTube videos, and social media posts . But, most styles have common elements on how to write references in a research paper.

when to cite a source in a research paper

Basic Citation Elements

Aside from the above mentioned, it’s important to note that there are two aspects to consider on how to write a citation in a research paper: in-text and the reference list section. In-text citations are included in the body of your work. These are also repeated but in more detail in the reference list usually situated after your article. Different levels of styles have different ways to cite works. However, they usually include the critical information listed above.

Furthermore, the choice of citation styles or formats largely depends on your discipline, your institution, and other venues for publication (e.g., journals and conferences). So, it is best to check your target venue for submission for its preferred citation style. It is also good to note that some have specific style preferences, apart from the popular formats (e.g. APA, MLA, Chicago, and IEEE). Hence, it is best to check the author’s instructions page on their websites and articles that have already been published for reference.

Appropriate Level of Citation: Undercitation, Overcitation, and Unethical Citations

Just like most things, citation in research should be done in a reasonable amount. You must avoid undercitation and overcitation. The former is when you miss out to cite a source while the latter is when you put unnecessary citations that can be too distracting (Appropriate Level of Citation, n.d.). By citing all utilized sources used and giving proper credit to actual authors, scholarly writers do not only prevent plagiarism but also show that they have conducted extensive research, are well-informed about the study subject, and their research is reliable (Truluck & Richardson, 2013).

In this section on how to make citations in research, we will discuss when you must cite a source and how to avoid overcitation.

When to Cite a Source

The components in a citation or reference entry are devised to allow the reader to identify or locate the specific source that is cited (Lanning, 2016). Whenever you use another individual’s work, you really must cite a source. Forgetting to or intentionally not doing so can lead to a serious dent on your reputation. Thus, remember to cite properly when you:

When writers fail to cite their sources, they commit undercitation, as the APA (n.d.) calls it. This leads to plagiarism. This is really frowned upon not just in the academic research community. It is also a no-no in every type of publication, from films to music. So, it is best to be really thorough in collecting and referencing your sources. Learning how to cite papers is simple. But, you also have to be careful not to be too thorough. Too much care or fear of undercitation can lead to overdoing them.

Putting more citations than required is called overcitation. This is also frowned upon but to a somewhat lesser extent. The reasoning here is that when you place inappropriate amounts of citations, it can be quite distracting for readers. This is especially true when dealing with in-text citations. Readers and reviewers will find it difficult to follow the thoughts and arguments in your paper if they are constantly getting interrupted by unnecessary in-text citations. It can really become annoying. The key to writing a coherent research paper lies in knowing how to cite a study and when to add in-text citations.

Overcitation usually happens when writers repeat the same citation in every sentence even though the topic and source have not changed at all. To avoid overdoing citations when paraphrasing, remember to place a citation for a key point in a paragraph only in the first sentence where it is relevant. Do not repeat the citation when the source of the material remains clear and the same.

Moreover, overcitation can also be very unethical especially when a writer cites a source as evidence even when the source does not really count as one. This unethical practice usually happens when a writer cites a study or dataset to support a claim but when reviewers and readers go through the source, they would find it not to be valid evidence for the writer’s claim. Sometimes, this can happen unintentionally, especially when a writer misunderstands what was cited or the implications of the information cited. But, there can be instances when there is malicious intent to boost the credits of a claim by beefing up cited works. This must be avoided at all costs.

Furthermore, it is highly discouraged for writers to cite themselves especially when their works are unrelated. It may be quite tempting to cite your work or your colleagues’ to boost your profiles or publications. But, this should be avoided to keep the integrity of the current work. Reviewers and other researchers are able to recognize self-promotion when they see it. Keep in the context of the work and keep unrelated stuff and self-promotion out of it.

In the next few sections, we’ll provide basic guides on how to cite various sources using four popular citation formats: (1) APA, (2) MLA, (3) Chicago/Turabian, and (4) IEEE.

APA stands for American Psychological Association. The APA style for citation is popular among behavioral and social science journals. However, it is not limited to such disciplines. The style originated in 1929, created by a group of psychologists, anthropologists, and business managers to improve reading comprehension (University of Pittsburgh, 2020). The citation style has undergone many changes throughout the years.

The latest version is the APA 7th edition published in October 2019. This section draws from the APA official Style and Grammar Guidelines (American Psychological Association, n.d.).

The guidelines on how to add references in a research paper, including in-text citation, formatting of the reference list, or bibliography section are explained in this section.

APA In-Text Citation

In-text citations let users know which ideas are attributed to whom. The APA citation style has two major elements for in-text citation: the author and the date. Also, they come in two forms: parenthetical and narrative (APA, 2019).

Parenthetical Citations

For parenthetical citations, both author and date appear separated by a comma. A parenthetical citation may appear within or at the end of a sentence.

Should other texts appear within the parenthetical citation, one should use commas around the year.

If both text and citation are included in parentheses, use a semicolon to separate them. Never use parentheses within parentheses.

Narrative Citations

In narrative citations, the author’s last name appears in the running text while the date appears in parentheses after it. The author’s name can be placed in any part of the sentence that makes sense.

In cases where both the author and date element appear in the running text, do not use parentheses.

Citations by the Number of Authors

For a single author 

For two authors

For three to five authors

For six or more authors

If the author information is not available, you can use the source title to replace the author element. When there is no date included in the source, cite the first few words of the article inside quotation marks using a headline-style capitalization with the year after the comma in your in-text citation in the form:

APA Reference List Entries Format

For the reference lists located at the end of the research paper, you need to cite four major elements:

Below are the APA style rules for each of them.

APA Individual Author Names Format

When citing individual author’s names, write the surname first. This is followed by a comma then the author’s initials.

If there is more than one author, place a comma to separate an author’s initials from subsequent author names. This is also applicable even when there are only two authors. Also, use an ampersand “&” before the final author’s name and put one space between initials.

Include both surnames and initials or up to and including 20 authors. Again, in this case, use an ampersand before the last author’s name.

If there are 21 authors or more, include the first 19 authors’ names, then insert an ellipsis before adding the final author’s name. Note that you should not use an ampersand in this case.

Moreover, it is important to write the author’s name as it appears in published works. This does not only include two-part surnames and hyphenated surnames but also the author’s preferred capitalization.

Group Author Names Format

Usually, group authors come in the form of task forces, non-profit organizations, and government agencies. When only the name of the group is used on the cover or title page of a publication, treat it as having a group author. This is even the case when individuals are credited elsewhere in the work itself like the acknowledgment section. However, if there are individual names in the cover or title page, treat the work as having multiple individual authors.

For the reference list entry, you should spell out the full name of the group then add a period after it.

You can use the abbreviation of the group in the text (e.g. APA for the American Psychological Association).

Use the most specific agency as the author when there are various layers of government agencies listed. Parent agencies not appearing in the group author name should be found in the source element as the publisher of the work.

Date Format

For most publications, you only use the year. Put the year of publication inside parentheses followed by a period.

For others that require day, month, and/or season along with the year, place the month and date or season after the year. Separate them with a comma.

If the work you are citing has been accepted for publication yet is still to be published, use “in press” instead of the year. However, for in-progress works, unpublished papers, and informally published documents, never use “submitted for publication” or “in progress.” Instead, give the year the work was produced instead. Also, if you are citing a work that is an advanced online publication, use the year of the advanced online publication.

For dates with an approximate date of publication use “ca.” for “circa” before the year.

If you want to cite publications that are designed to change over time, you would need to provide the retrieval date for the document. Use this following format:

If there is no date available, again, use “n.d.” The entry can take the form of:

Title Format

There are two main kinds of titles. Firstly, titles can be the name of the standalone work like books and research papers. In this case, the title of the work should appear in the title element of the reference. Secondly, they can be a part of a bigger work, such as edited chapters, podcast episodes, and even songs. In this case, the title of the article or chapter or part of the work should appear in the title element. The title of the bigger work should appear in the source element.

For standalone works, italicize the title. Also, use sentence case.

When citing parts of a bigger work like an edited chapter or journal articles, capitalize the title using sentence case. Do not, however, italicize the title or place it between quotation marks.

If there are different editions, volumes, or report numbers, include these after the title enclosed in parentheses. Do not use a period to separate the title and the parenthetical. If both volume information and edition are included, use a comma as a separator and put the edition number first.

When the numbered volume has its own title, both of them should be included as part of the main title instead of the parenthetical information. Also, the title element should be finished with a period whenever the title does not end with a question mark or exclamation point. In cases where titles do, use the appropriate punctuation marks.

When citing works outside the peer-reviewed academic literature, give a description of the work in square brackets after the title but before the period. You should capitalize the first letter but do not italicize the description. Do this for YouTube videos, audiobooks, manuscripts in preparation, theses, and others. Moreover, bracketed descriptions can also be used for social media references.

Source Format

Different sources require different formatting conventions. There are usually six types of source references commonly cited: journal articles, conference papers, authored book or whole edited book, edited book chapter, webpage on a website with authors different from the site name, and webpage on a website where authors name is the same with the site.

For journal articles, there are five components: periodical title, volume, issue, page range, and DOI or URL. So, for the article with the title “The Basic Problem of the Theory of Levels of Reality” by Roberto Poli published in 2001, you write the reference as:

Above, “Axiomathes” is the name of the journal, “12” is the volume number, “3” is the issue number, and “261-283” is the page range.

When citing a paper or session in a conference that is not formally published in the proceedings, the format is:

When citing an authored book or whole edited book, provide the name of the publisher and the DOI or URL. The format is:

And, when citing a book chapter for edited books, you cite each chapter separately. When citing more than one chapter, you cite each chapter as a different source. The format is:

For webpages that have different authors’ names from the site name, provide the website name and the URL for the source element. For webpages whose authors’ names are the same as the site, only provide the URL.

Database Information

In APA style references, DOIs and URLs are used. DOI is short for digital object identifiers. These are alphanumeric strings identifying unique content while providing a persistent link to their locations. You can find these in database records and reference lists.

DOIs come in the form of: “https://doi.org/xxxxx” where “xxxxx” is the DOI number. On the other hand, URL is short for uniform resource locators. These are basically the links you find on the address bar of your browser. So, when do you include DOIs and URLs? Here are the APA guidelines.

In the APA style, you do not include other alphanumeric identifiers, such as the International Standard Serial Number (ISSN) and the International Standard Book Number (ISBN). Also, when using DOIs and URLs, present them as hyperlinks. This means they begin with “http:” or “https:”.  And, it is acceptable to display the link in blue font and underlined like in the default setting in your word-processing software or you can use plain text.

Examples of APA Reference List

In this section, an example of a reference list containing different types of sources that you could use as a quick guide.

Chapter of an Edited Book

Journal Article

Conference Paper/Presentation


MLA is short for the Modern Language Association based in the U.S. The MLA style is used worldwide and is popularly used in the humanities. The latest version is the 8th edition published in 2016. And, just like APA, it has in-text citation and reference list rules. However, when you use the MLA format, you use the title “Works-Cited List” for your reference list. In this section, the rules for both in-text citation and the works-cited list will be discussed.

MLA In-Text Citation

The MLA in-text citations have two elements: the author’s surname and the page or page-range where the reference is found. MLA style in-text citations also come in two forms: parenthetical and narrative. Also, they are usually inserted immediately after a quote or parenthetical or in a natural pause. In-text references are used to reference works that you quote or paraphrase from. The latest version is the MLA 8th edition (Mendeley, 2019).

If there are more two to three authors, they should be cited in the following format.

For more than three authors, you only include the surname of the first author followed by “et al.” such as:

If there are no authors, you should italicize the whole title for books. For articles, you enclose the title in quotations. Also, you can use a shortened title within quotation marks instead of the author’s name.

For authors with multiple cited works, include a shortened version of the title within the citation.

In cases where authors have the same surnames, you should include an initial to differentiate.

If there are no page numbers, then include the number pattern included in the book like chapters or paragraphs. If there are no numbered sections, then only the name should be included.

When citing a quote or a parenthetical, use “qtd.” before the author’s name.

Also, when citing audio-visual sources, use a timestamp instead of a page number. The format should be in “hh:mm:ss”.

MLA Works-Cited List

The MLA style uses a “Works-Cited List” instead of a reference list on a new page after the document. This list contains all the sources referenced in the document containing different elements, depending on the source type. Moreover, it is also ordered alphabetically by the name of the first author or title (when the author is unknown). Also, when alphabetizing, you should ignore the articles “a,” “an,” and “the.”

Furthermore, if there are multiple works by a single author, you should order these by date. If the works were published in the same year, order them alphabetically by the title. Also, the first reference must contain the full name of the author. Subsequent references should have author name replaced by “- – -.”

Format-wise, entries must be double spaced and the second and subsequent lines of the source are indented by half an inch from the margin.  Also, different types of sources cited require different formats for citation.

MLA Style Citation for Books, Chapters (or Essays) in a Book, and E-Books

The basic structure for citing books is:

When there are two authors, the first author’s name should be written surname first while the second author’s name should be written in its normal order. There should be an “and” between both names.

For three or more authors, provide the first author’s name surname first then followed by “et al.”

When you want to cite a chapter or an essay in a book, follow this basic format.

For e-books, the basic format is as follows:

MLA Style Citation for Journals, Newspaper/Magazines, and Online Publications

Citing journals, newspapers, magazines, and online articles have the same basic format in MLA:

Here are a few examples:

To cite a webpage, use this basic format:

MLA Citation for Non-Print Materials: Images, Music, Film, and TV Series

When citing the image, follow the following format:

For music, citations come in the form of:

Films/movies can be cited using two different formats. You put the movie title first when you focused more on the film rather than the director. Otherwise, when you focus more on the director, provide the director’s name first.

To cite TV or a web series, you should include the episode and season number.

Chicago and Turabian are interchangeable. The latter is a much simpler style aimed at students whose works are not intended for publishing. However, both are considered to be the official Chicago style (Hansen, 2011). The Chicago style has two citation style conventions: the notes and bibliography style and the author-date style. Both of these appear in  The Chicago Manual of Style .   The latest version is the 8th edition (University of Chicago Press, 2017a).

The notes and bibliography style is popular in the humanities, literature, and the arts. It uses a footnotes or endnotes system. Each note has a corresponding superscript number in the text. On the other hand, the author-date style cites sources briefly in the text by the author’s last name and the year of publication of the work. Each citation in both conventions has matches in a separate reference list at the end of the document.

[table “chicagostyle” could not be loaded /]

We will discuss the two conventions below including some examples.

Notes and Bibliography Style

For this convention, you use a raised number or superscript. These are usually placed at the end of sentences (University of Chicago Press, 2017b). This is used to let readers know that a sentence contains information from a different source. Each superscript corresponds to an item on the footnotes (notes located at the bottom of a page) or endnotes (notes located at the end of a paper, chapter, or book).

The full footnote citation for a book takes the form of:

If you cite a work multiple times, you can use a shortened version such as:

For the bibliography section, entries should be in alphabetical order. They come in the form of:

The citation formats for different sources are identical in both the notes and bibliography style and the author-date style. The only difference is the in-text citation. The latter provides in-text mentions of the last name of the author and publication date instead of a corresponding superscript.

Author-Date Style: In-Text Citations and Citing Different Sources on the Reference List

In-text citations provide the author’s last name, the year of publication, and the page or page range. Only use a comma to separate the publication year and the page. Do not use a comma in between the author’s last name and publication date (University of Chicago Press, 2017c).

Citing a book in the reference list has the same format as citing a book on the other convention’s bibliography entry discussed in the previous subsection. For citing a chapter or some part of an edited book, cite specific pages in the text and include the page range for the chapter or part in the reference list.

When there are multiple authors provide the last name first for the first author and list the subsequent authors using their first names first. Also, separate the names using commas and at the end of the authors element place a period.

When citing an edited book as a whole, provide the editor(s) name first.

If you are citing a translated book, follow this format:

When citing an e-book, the in-text citation takes the same form as others. However, for the reference list entry, you should include a URL or the name of the database. For other types of e-books, provide a format like Kindle, among others.

When citing a book review, indicate that it is a review and of what material after the title.

If you are citing a thesis or dissertation, the basic format you should follow is:

For journal articles, you should include the page range of the whole article you are citing. Also, you should cite specific page numbers in the text. If you are using online articles, use a URL or the database name in the reference list entry. However, a DOI is preferred over a URL.

When there are four or more authors, list up to ten in the reference list. For the citation in the text, only provide the surname of the first author followed by “et al.”. If there are more than ten authors, just list the first seven in the reference list and add “et al.”.

The rules for citing news or magazine articles are the same. It is the same with blog sites and news sites as well. Under the reference list, it is highly recommended that you repeat the year in sources that you also cite with a month and day. Moreover, you should cite the page numbers, if any, in the text. But, leave these out in the reference list entries. And, if you are citing an online article, provide the name of the database or the URL.

When citing website content, do include the access date especially if the webpage is designed to get upated or changed. Also, use “n.d.” for no date if the site does not list a date of publication, revision, or posting. Here are some examples:

For audiovisual content, the citation format is quite similar to the others here. However, one should provide contributors, content type, and timestamp or clip length. Here is an example:

When citing social media content, providing the quoted text is already enough in your document. For more formal citation, you should consider providing a link and a reference list entry. When you do, in place of a title, quote the post with up to the first 160 characters.

Moreover, comments are cited in reference to the original post. And, you should include the date and time of the comment in the in-text citation in the form:

The IEEE citation style is mainly used for reports in electronics, engineering, computer science, telecommunications, and information technology. IEEE is the official style of the eponymous Institute of Electrical and Electronics Engineers. There are three main parts of an IEEE-style reference. They are:

Just like other popular citation styles, the format and inclusion of punctuations, page numbers, dates, and other information vary according to the types of references cited. Also, the IEEE style has both in-text and reference list citations.

IEEE In-Text Citation

In the IEEE style, each citation is noted in the text using simple sequential numbers enclosed in square brackets:  “[number]”. Also, they should be in the same line as the text and appear before any punctuation with a space before the bracket. Each bracketed number corresponds to a specific work and citations are numbered in the order of their appearances. In cases where the same source is cited, the same number is used in other citation instances. Moreover, no distinction is made between print and electronic sources. Distinguishing information is included in the references list (IEEE, n.d.).

IEEE Reference List Citation

Different source types get cited differently in the IEEE style. But, the basic principle applies just like other citation styles. Citations basically answer the who, what, when, and where questions. In this section, we will provide a general format for major document types and some citation examples.

Print Documents

For published works, the titles are italicized and capitalized. On the other hand, you do not italicize the titles of unpublished works. And, you only capitalize the first word for the titles. Also, authors’ names are written with initials first then their surnames. For two authors, each name is separated with the word “and.” For three or more authors, you only use the word “and” before the last author’s name. Also, you end the author element with a comma.

Internet Documents and Software

For online documents and digital software, one needs to include the format using “[format]”. For online sources, provide the URL using this format “Available: URL.” Also, provide the access date with “[Accessed Month Day, Year]” Also, there are different ways of citing different source types.

There are many other document types and examples that we cannot cover here. It is best to check the official IEEE style guide for more.

Citation Styles Summary

The table below can serve as a quick guide to help you cite your sources properly. In case you are using other data sources for your research, you may also consult this guide on how to cite a PowerPoint in APA.


Related Articles

Needs Analysis: Definition, Importance & Implementation

Needs Analysis: Definition, Importance & Implementation

by Imed Bouchrika, Phd

How to Write a Scope of Work: Examples & Templates

How to Write Research Methodology: Overview, Tips, and Techniques

How to Write Research Methodology: Overview, Tips, and Techniques

How to Write a Thesis Statement for a Research Paper: Steps and Examples

How to Write a Thesis Statement for a Research Paper: Steps and Examples

Top 10 Qualities of Good Academic Research

Top 10 Qualities of Good Academic Research

How to Write a Research Question: Types, Steps, and Examples

How to Write a Research Question: Types, Steps, and Examples

Major Philosophers and Their Ideas: Past and Future Wisdom

Major Philosophers and Their Ideas: Past and Future Wisdom

APA Format for Academic Papers: Guidelines & Examples

APA Format for Academic Papers: Guidelines & Examples

How to Write a Research Paper for Publication: Outline, Format & Types

How to Write a Research Paper for Publication: Outline, Format & Types

How to Cite a PowerPoint Presentation in APA

How to Cite a PowerPoint Presentation in APA

What Is A University Dissertation: 2023 Structure, Challenges & Writing Tips

What Is A University Dissertation: 2023 Structure, Challenges & Writing Tips

Definition of  Academic Research

Definition of Academic Research

What Can You Do with a Criminal Psychology Degree: 2023 Costs & Job Opportunities

What Can You Do with a Criminal Psychology Degree: 2023 Costs & Job Opportunities

Best Online Nursing Degree Programs of 2023

Best Online Nursing Degree Programs of 2023

Best Online Digital Marketing Degree Programs of 2023

Best Online Digital Marketing Degree Programs of 2023

Best Online Graphic Design Degree Programs of 2023

Best Online Graphic Design Degree Programs of 2023

Finance Careers: 2023 Guide to Career Paths, Options & Salary

Finance Careers: 2023 Guide to Career Paths, Options & Salary

Best Online Teaching Degree Programs of 2023

Best Online Teaching Degree Programs of 2023

Newsletter & conference alerts.

Research.com uses the information to contact you about our relevant content. For more information, check out our Privacy Policy .

Newsletter confirmation

Thank you for subscribing!

Confirmation email sent. Please click the link in the email to confirm your subscription.

bullhorn icon

When should I use a citation?

Citing Sources: When should I use a citation?

A citation should be used when content that did not originate with you is used to support your writing.

Content includes:

Here are a few pages fr om Excelsior OWL's guide to writing process to get you started:

What you don't need to cite

No need to cite what is known as common knowledge.

But, what is common knowledge?  Common knowledge includes information that someone can easily trace and find the answer to.  In an academic context, common knowledge will depend on the audience, but here are some examples to get you started:

For more examples of how to determine if something is common knowledge, check out this resource :

When in doubt: CITE --  You won’t be judged harshly for adding a citation when it isn’t needed.  However, skipping a citation (whether it’s an accident or not) is considered plagiarism, which can have serious consequences.

Organizing Your Social Sciences Research Paper

A citation is a formal reference to a published or unpublished source that you consulted and obtained information from while writing your research paper. The way in which you document your sources depends on the writing style manual your professor wants you to use for the class [e.g., APA, MLA, Chicago, Turabian, etc.]. Note that some disciplines have their own citation method [e.g., law].

Importance of a Citing your Sources

Citations document for your readers where you obtained your material, provide a means of critiquing your study based on the sources you used, and create an opportunity to obtain information about prior studies of the research problem under investigation. The act of citing sources is also your best defense against allegations of plagiarism.

Citing the works of others is important because:

NOTE:   In any academic writing, you are required to identify which ideas, facts, thoughts, and concepts are yours and which are derived from the research and work of others. Whether you summarize, paraphrase, or use direct quotes, if it's not your original idea, the source must be acknowledged. The only possible exception to this rule is information that is considered to be a commonly known fact [e.g., George Washington was the first president of the United States]. Appreciate, however, that any "commonly known fact" is culturally constructed and shaped by social and aesthetical biases . If you are in doubt about whether or not a fact is common knowledge, protect yourself from an allegation of plagiarism and provide a supporting citation, or, ask your professor for clarification about how a factual statement should be cited.

Ballenger, Bruce P. The Curious Researcher: A Guide to Writing Research Papers . 7th edition. Boston, MA: Pearson, 2012; Citing Information. The Writing Center. University of North Carolina; Harvard Guide to Using Sources. Harvard College Writing Program. Harvard University; Newton, Philip. "Academic Integrity: A Quantitative Study of Confidence and Understanding in Students at the Start of Their Higher Education."  Assessment and Evaluation in Higher Education 41 (2016): 482-497; Referencing More Effectively. Academic Skills Centre. University of Canberra; Using Sources. Yale College Writing Center. Yale University.

Structure and Writing Style

Referencing your sources means systematically showing what information or ideas you are quoting or paraphrasing from another author’s work, and identifying where that information come from . You must cite research in order to do research, but at the same time, you must delineate what are your original thoughts and ideas and what are the thoughts and ideas of others. Procedures used to cite sources vary among different fields of study. Always speak with your professor about what writing style for citing sources should be used for the class because it is important to fully understand the citation style to be used in your paper, and to apply it consistently. If your professor defers and tells you to "choose whatever you want, just be consistent," then choose the citation style you are most familiar with or that is appropriate to your major [e.g., use Chicago style if its a history class; use APA if its an education course; use MLA if it is literature or a general writing course].


1. Should I avoid referencing other people's work? No! If placed in the proper context, r eferencing other people's research is never an indication that your work is substandard or lacks originality. In fact, the opposite is true. If you write your paper without adequate references to previous studies, you are signaling to the reader that you are not familiar with the literature about the topic, thereby, undermining the validity of your study and your credibility as a researcher. Including references in academic writing not only defends you against allegations of plagiarism, but it is one of the most important ways to demonstrate your knowledge and understanding of previous investigations about the research problem. It is the intellectual packaging around which you present your study to the reader.

2. What should I do if I find that my idea has already been examined by another researcher? Do not ignore another author's work because doing so will lead your readers to believe that you have either borrowed the idea or information without properly referencing it [this is plagiarism] or that you have failed to conduct a thorough review of the literature. You can acknowledge the other research by writing in the text of your paper something like this: [see also Smith, 2002], then citing the complete source in your list of references. Use the discovery of prior research as an opportunity to demonstrate the significance of the problem being investigated and, if applicable, as a means of delineating your analysis from those of others [e.g., the prior study is ten years old and doesn't take into account new variables]. Reacting to prior research can include: stating how your study updates previous studies on the topic, offering a new or different perspective, using a different method of data gathering, and/or describing a new set of guidelines, recommendations, best practices, or working solutions.

3. What should I do if I want to use an adapted version of someone else's work? You still must cite the original work. For example, maybe you are using a table of statistics from a journal article published in 1996 by author Smith, but you have altered or added new data to it. Reference the revised chart, such as, [adapted from Smith, 1996], then cite the complete source in your list of references. You can also use other terms in order to specify the exact relationship between the original source and the version you have presented, such as, "based on Smith [1996]...," or "summarized from Smith [1996]...." Citing the original source helps the reader locate where the information was first presented and under what context it was used as well as to evaluate how effectively you applied it to your own research.

4. What should I do if several authors have published very similar information or ideas? You can indicate that the idea or information can be found in the work of others by stating something similar to the following example: "Though in fact many scholars have applied this theory to understanding economic relations among nations [for example, see Smith, 1989; Jones, 1991; Johnson, 1994; Anderson, 2003], little attention has been given to applying the theory to examining the actions of non-governmental organizations in a globalized economy." If you only reference one author or only the most recent study, then your readers may assume that only one author has published on this topic, or more likely, conclude that you have not conducted a thorough literature review. Referencing all relevant authors of prior studies gives your readers a clear idea of the breadth of analysis you conducted in preparing to study the research problem. If there has been significant number of prior studies on the topic, describe the most comprehensive and recent works because they will presumably discuss and reference the older studies. However, note that there has been significant scholarship devoted to the topic so the reader knows that you are aware of this.

5. What if I find exactly what I want to say in the writing of another researcher? In the social sciences, the rationale in duplicating prior research is generally governed by the passage of time, changing circumstances or conditions, or the introduction of new variables that necessitate a new investigation . If someone else has recently conducted a thorough investigation of precisely the same research problem as you, then you likely will have to revise your topic, or at the very least, review this literature to identify something new to say about the problem. However, if it is someone else's particularly succinct expression, but it fits perfectly with what you are trying to say, then you can quote it directly, referencing the source. Do not see this as a setback or become discouraged if you discover that your brilliant idea or important insight has already been identified by someone else. Identifying an author who has made the same point as you can be an opportunity to add legitimacy to, as well as reinforce the significance of, the research problem you are investigating. The key is to build on that idea in new and innovative ways. If you are not sure how to do this, consult with a librarian!

6. Should I cite a source even if it was published long ago? Any resource used in writing your paper should be cited, regardless of when the study was written. However, in building a case for understanding prior research about your topic, it is generally true that you should focus on citing more recently published studies because they presumably have built upon the research of older publications. This is particularly true of new or revised editions of books, unless an older edition has unique information not carried over into newer editions. When referencing prior studies, use the research problem as your guide when considering what to cite. If a study from forty years ago investigated the same research problem, it probably should be examined and considered in your list of references because the research may have been foundational or groundbreaking even if its findings are no longer relevant to current conditions or reflect current thinking [one way to determine if a study is foundational or groundbreaking is to examine how often it has been cited in recent studies using the "Cited by" feature of Google Scholar ]. However, if an older study only relates to the research problem tangentially or it has not been cited in recent studies, then it may be more appropriate to list it under further readings .

Ballenger, Bruce P. The Curious Researcher: A Guide to Writing Research Papers . 7th edition. Boston, MA: Pearson, 2012; Harvard Guide to Using Sources. Harvard College Writing Program. Harvard University; How to Cite Other Sources in Your Paper. The Structure, Format, Content, and Style of a Journal-Style Scientific Paper. Department of Biology. Bates College; Lunsford, Andrea A. and Robert Connors; The St. Martin's Handbook . New York: St. Martin's Press, 1989; Mills, Elizabeth Shown. Evidence Explained: Citing History Sources from Artifacts to Cyberspace . 3rd edition. Baltimore, MD: Genealogical Publishing Company, 2015; Research and Citation Resources. The Writing Lab and The OWL. Purdue University; Writing Tutorial Services, Center for Innovative Teaching and Learning. Indiana University.

Citation Research Guides

The following USC Libraries research guide can help you properly cite sources in your research paper:

The following USC Libraries research guide offers basic information on using images and media in research:

Listed below are particularly well-done and comprehensive websites that provide specific examples of how to cite sources under different style guidelines.

This is a useful guide concerning how to properly cite images in your research paper.

This guide provides good information on the act of citation analysis, whereby you count the number of times a published work is cited by other works in order to measure the impact of a publication or author.

Measuring Your Impact: Impact Factor, Citation Analysis, and other Metrics: Citation Analysis [Sandy De Groote, University of Illinois, Chicago]

Automatic Citation Generators

The links below lead to systems where you can type in your information and have a citation compiled for you. Note that these systems are not foolproof so it is important that you verify that the citation is correct and check your spelling, capitalization, etc. However, they can be useful in creating basic types of citations, particularly for online sources.

NOTE:   Many companies that create the research databases the USC Libraries subscribe to, such as ProQuest , include built-in citation generators that help take the guesswork out of how to properly cite a work. When available, you should utilize these features because they not only generate a citation to the source [e.g., a journal article], but include information about where you accessed the source [e.g., the database].


  1. 52 best images about Bibliography/Citing Sources on Pinterest

    when to cite a source in a research paper

  2. 021 How To Cite Sources In An Essay Example College Writing Citing ~ Thatsnotus

    when to cite a source in a research paper

  3. Télécharger Works Cited Mla In Text Citation Example

    when to cite a source in a research paper

  4. 014 Samplefirstpagemla Research Paper Mla Format Citing ~ Museumlegs

    when to cite a source in a research paper

  5. 007 Mla How To Cite Source In Research Paper ~ Museumlegs

    when to cite a source in a research paper

  6. Beautiful How To Cite A Source In An Essay ~ Thatsnotus

    when to cite a source in a research paper


  1. Research Citation & Referencing

  2. Word. References menyu

  3. Free Citation Website for Research Papers

  4. Gabriel Galice à Brochu en direct

  5. Citation Practices

  6. How can we cite more than one references in text reference from only one research paper ??


  1. When to Cite

    You must cite the source every time you incorporate research, words, ideas, data, or information that is not your own (2). While you are synthesizing and

  2. Warning: When You Must Cite

    When you quote two or more words verbatim, or even one word if it is used in a way that is unique to the source. · When you introduce facts that you have found

  3. Cite Your Sources

    In the body of a paper, the in-text citation acknowledges the source of information used. · At the end of a paper, the citations are compiled on a References or

  4. When to Cite

    Cite when you are directly quoting. This is the easiest rule to understand. · Cite when you are summarizing and paraphrasing. · Cite when you are citing something

  5. When and Why to Cite Sources

    When to cite sources · 1. Direct quotes of more than one word. · 2. Paraphrasing or summarizing. · 3. Information which may be common knowledge but still

  6. What Information Should be Cited and Why?

    In general, you must document sources when you provide information that you ordinarily would not have known before conducting your research, and when you

  7. To Cite or Not to Cite?

    When do I need to cite sources? · Writing your own lived experiences, your own observations and insights, your own thoughts, and your own

  8. How To Cite a Research Paper: Citation Styles Guide

    To Give Details on Source Documents – Citations make it easier for reviewers to check for data and even the line of arguments. Also, it helps direct the readers

  9. Citing Sources: When should I use a citation?

    words (quotations, phrases, sayings, etc.) · thoughts or ideas (summarizations and paraphrases) · audio or visual material (photos, videos

  10. 11. Citing Sources

    Citations document for your readers where you obtained your material, provide a means of critiquing your study based on the sources you used