How to Cite Your Sources

Making reference to our work's sources is an important part of academic research and writing, but for many students it is a daunting and misunderstood process. This guide provides teachers and students with a comprehensive list of resources for learning about citations in academic writing, including how and when to use them. You'll find introductions to the official style guides for the most popular citation formats, instructions on how to spot and prevent plagiarism, and links to additional resources for teaching and learning about academic citation methods. 

Fundamentals of Academic Citations

Citations are a fundamental part of most academic writing, and must be used whenever you make use of thoughts or observations that are not completely your own. Citations serve two main purposes:

  • They attribute source material, such as an academic journal or book, to the person or people who created it.
  • They enable further research for readers interested in learning more about the topic of the cited material.

Before you begin researching and writing your own academic papers and essays, it's important to understand the fundamentals of citations. 

What is a Citation?

In order to research and write academic work correctly and honestly, you must have a clear understanding of what a citation is. The resources below will give you a solid grounding in the fundamentals of why we use citations and when to use them in your own work.

"Citations" (Wikipedia) 

Wikipedia's entry on citations includes thorough descriptions of their function and purpose, as well as subsections dedicated to different citation styles.  

Video Tutorial on Citations (North Carolina State Univ. via YouTube) 

This video describes what a citation is, why we cite, and what kinds of citation styles you are likely to encounter. This video could be especially helpful as a succinct guide for visual learners.

MIT Library Guide  

The Massachusetts Institute of Technology's library guide has a helpful section on citation basics, including an entire section on  when you must cite your sources.  

"What is a Citation?" ( 

This page defines citations and details when to use them. is a comprehensive resource for understanding and preventing plagiarism (which we will discuss in the next section). 

Citation vs. Reference: What's the Difference? (Learning, Teaching, and Leadership Blog)

This blog post by a professor at the University of Calgary clarifies the subtle but important difference between a citation (a source mentioned within the context of a paper or essay) and a reference (an entry in a compiled list of sources cited in your work). 

Why Using Citations Is Important

Citations enable further research, prevent the spread of false information, and give credit to the creator of an original idea. By using citations correctly, you can be sure to avoid plagiarism, the "theft of ideas," which can have serious consequences. To understand how to use citations and prevent plagiarism, you'll need a solid grounding in what plagiarism is and how to spot it. 

"What Is Plagiarism?" ( 

This article defines plagiarism as an "act of fraud" which involves both "stealing" and "lying about it afterward." The article contains sections on intellectual property and the theft of ideas, both crucial concepts in understanding plagiarism. 

Purdue OWL Article on Plagiarism 

This piece frames plagiarism within the context of "intellectual challenges" that writers must overcome in order to achieve true academic credibility. 

St. John's Univ. Video on Plagiarism (YouTube) 

This video clip includes interviews from multiple St. John's University faculty and students, who all give their thoughts on defining and preventing plagiarism.

Avoiding Plagiarism

Many people believe that plagiarism occurs only when you use another writer's words verbatim in your own work. That is plagiarism, of course, but it's not the only form. As a result of misunderstanding the term's nuances, many students commit plagiarism unintentionally. The resources below demystify the main types of plagiarism. 

The Main Types of Plagiarism 

There are four main types of plagiarism: direct plagiarism, patchwriting (also known as "mosaic plagiarism"), self-plagiarism, and accidental plagiarism. Below we provide a quick definition of each, with links to more in-depth explanations. 

  1. Direct plagiarism: Word-for-word copying of someone else's work. 
  2. Patchwriting: Paraphrasing from someone else's work, even if the source is cited. 
  3. Self-plagiarism: The practice of making one's own previously published ideas appear brand new.  
  4. Accidental plagiarism: Unintentionally or subconsciously using someone else's words or expression of ideas as your own. The consequences of accidental plagiarism are typically the same as those of any other type of plagiarism. The video linked here explains how to avoid accidental plagiarism. 

When You Must Use Citations

The most effective way to avoid plagiarism and cite your sources properly is by understanding exactly when you need to use citations (and when you do not). The links below will help clarify those situations. 

"When to Cite Sources" (Princeton Univ.)

Princeton's department of Academic Integrity offers this dense but highly informative and thorough breakdown of when citations are required. 

Academic Integrity Handbook: "What is Common Knowledge?" (MIT) 

You may have heard that you do not need to cite your source when the statement is considered "common knowledge." This resource from MIT discusses when a topic can be considered common knowledge, and therefore does not require citation.

"Teaching Students to Avoid Plagiarism" (Cult of Pedagogy Blog)

The Cult of Pedagogy blog has an informative in-depth guide on the importance of citations, written by a former middle school teacher. The guide contains exercises, teaching strategies, and a podcast version of the entire post. 

"Citing Sources: When You Don't Need to Cite" (Davidson College) 

Like the MIT handbook's section on "common knowledge," this guide from Davidson College explains situations in which citations are not required. 

"Don't Plagiarizzle" (YouTube)

Students will enjoy this video of a rap song, which teaches them when to cite and how to avoid plagiarism. The video is aimed at an elementary school audience, but fun for all!

Free Online Plagiarism Detectors

There are many online services you can use to check your (or your students') assignments for plagiarism: some are free, and some require a paid subscription. Below is a short list of some of the most popular free online plagiarism detectors.

The Top 10 Free Plagiarism Checkers (eLearning Industry)

This guide ranks the top 10 free plagiarism checkers for teachers, and includes a short list of the pros and cons for each resource. 

This site will compare your pasted text to billions of web pages to detect for plagiarism. If the services detects plagiarism, it also includes a "Citation Assistant" to help you cite the source properly. You will need to create an account to do more than a few searches.

This site provides free online plagiarism checking services by comparing the text you input to a database of "website content, academic work, and written text." The design is a bit tough to negotiate, but the software works for checking short blocks of text. 

Noplag is similar to Duplichecker and Quetext, but also offers a full-service paid version that checks entire papers and produces an annotated and highlighted report. The free version works for routine plagiarism checks and is among the best designed and fastest of the free services.

Paid Online Plagiarism Detectors 

Although there are many great free plagiarism detectors, there are also some more powerful paid options. LitCharts is not affiliated with any of these services, and presents them to you for educational purposes only. 

Perhaps the world's most popular paid plagiarism detection and prevention service, TurnItIn provides a detailed report on the percentage of plagiarized material in any document you input. Over 26 million students and teachers use TurnItIn.

Writecheck offers a  grammar and plagiarism review, and can be used for one or many assignments. The site also offers a grammar checker and tutoring.

Top 12 Online Paid Plagiarism Checkers (My e-Learning World) 

This ranked list from lays out the best plagiarism detectors for educators, comparing acceptable formats, features, and quality of price in a table-based format. 

The Most Popular Citation Styles

Academic citations come in many formats, often referred to as "styles," but you'll probably become most familiar with one of the four most popular citation styles listed below. Each style has its own complete set of guidelines on citations and grammatical conventions. Access to the complete style guides typically requires a paid subscription, but the links below point to free pages that recap each style's main citation formatting conventions.

MLA (Modern Language Association)

The Modern Language Association style is used most commonly within the liberal arts and humanities. The MLA Style Manual and Guide to Scholarly Publishing was first published in 1985 and (as of 2008) is in its third edition.

Chicago (Chicago Manual of Style)

Some call The Chicago Manual of Style, which was first published in 1906, "the editors' Bible." The manual is now in its 17th edition, and is popular in the social sciences, historical journals, and some other fields in the humanities.

APA (American Psychological Association)  

According to the American Psychological Association, this guide was developed to aid reading comprehension, clarity of communication, and for word choice that best reduces bias in language in the social and behavioral sciences. Its first full edition was published in 1952, and it is now in its sixth edition.

CSE (Council of Science Editors)

Scientific Style and Format: The CSE Manual for Authors, Editors, and Publishers, is geared specifically toward scientific papers. Its eighth edition was published in 2014.

Other Kinds of Citation Styles

Sometimes your field of study, your teacher's or professor's preferences, or the guidelines for a specific assignment will require you to use a set of citation styles other than the four most popular ones above. Below is a list of some of the most commonly used citation styles besides the "big four."

How to Choose a Citation Style

Citation styles differ for a reason. APA highlights where and when research was done, in order to make scientific material readily accessible to the reader. MLA, on the other hand, uses in-text citations with page numbers to enable easy referencing to sourced material. Your citation style depends heavily on the type of paper you’re writing, as well as the personal preferences of your professor. These resources will help you determine which style to use.

George Washington University Guide

This useful handbook from GWU provides a quick reference table matching several different disciplines to different citation styles. 

American University Style Manual

In this manual, American University offers a more comprehensive list of subjects matched to their respective citation styles. 

"Student's Guide to Citation Styles for Research Papers" (

This blog post for students from offers example citations for many different citation styles, and provides links to each one. 

PDF: "Choosing a Citation Style" (Immaculata Univ.)

This link from Immaculata University features a printable PDF handout with basic information for students on when to use the MLA, APA, and Chicago styles. 

The Most Common Citation Problems and Pitfalls

It is imperative that citations are not only included, but done correctly. Citations that are done incorrectly or "pulled" from the text just to satisfy a research requirement can often hurt a paper more than help it. There are solutions to these common problems, however, which we will outline in the section below. 

"Top Five Most Common Citation Mistakes" (First Editing)

First Editing, a writing review service, outlines several common citation mistakes and how to avoid them in this blog post. 

"Four Common APA Citation Mistakes" (

Geared specifically toward APA, this article from lists four common mistakes to avoid when using this citation style. 

"MLA In-Text Citations" (Lumen Learning)

About halfway down the page, this online course from Lumen Learning gives a few helpful examples of MLA citations done incorrectly

"Examples of Incorrect and Correct Citations" (McGraw Hill)

This webpage from a major academic publisher lists both correct and incorrect citations for an excerpt from Middlemarch. These examples serve as good visuals for how citations can go wrong. 

Citation Generators and Citation Management Software

Luckily, modern technology enables students and academics alike to compile their citations quickly and efficiently with the help of software applications. Listed below are some free online applications that can help you record, organize, and cite your research materials. 


EasyBib provides access to a greater range of citation formats than most other online citation makers. You can either input information directly into the template they provide, or have the service automatically scan for information. 

Citation Machine

Citation Machine supports MLA, APA, Chicago, and Turabian citation formats. You can either manually input the information from your source into the site, or have the service automatically scan a site you select. 

Citation Generator is a free and safe online tool that creates citation automatically. It supports the APA, MLA, and Chicago citation formats. Citation Generator allows users to cite anything with ease, from books to web pages, without the distraction of ads.


Zotero is a "personal research assistant" with both a full program and browser plug-in to organize citations. It also comes with a helpful tool that automatically scans sources for basic information, as well as writing an abstract for the piece. 


Although the service is limited without paying for a subscription, Bibme will check your paper for incorrect grammar, missing citations, and formatting mistakes. 

Resources for Teaching Students How to Use Academic Citations

Regardless of the discipline, it is imperative that students both appreciate the importance of citing sources and know how to properly cite. Citation also poses a unique pedagogical challenge—students usually don't find citation fun. Fortunately, there are many resources available to make teaching citations enjoyable for both the teacher and student.

"Put Some Excitement Into Citations!" (Informania Blog)

This blog post by an English teacher offers strategies for teaching citations, including presentations, classroom activities, and online citation games.  

Citation "Scavenger Hunt" Lesson Plan (ReadWriteThink)

This teaching blog breaks down a longer lesson plan into 50-minute segments, outlining different exercises you can do with your students to familiarize them with the conventions of citations. 

Citation Practice Games (Tomahawk School District Library)

This page contains links to several external citation practice games, including citation tic-tac-toe and drag-and-drop games. While these will likely appeal more to younger students, they could be a relaxed introduction to anyone unfamiliar with citation formats. 

"Teaching Citation and Documentation Norms" (Univ. of Michigan)

The University of Michigan's Writing Center suggests having students look carefully through a published journal article in your field, or giving them a particular research question as you teach them how to cite. 

Additional Resources on Academic Citation 

If you have more questions about academic citation after consulting the previous sections, the list of links compiled here will point you toward further resources. This list is by no means comprehensive, and we hope you will use it to uncover and research new topics. 

Purdue OWL Research and Citation Resources

Purdue OWL is an excellent source for anything related to writing or editing, and this page is no exception; the link above will help you find the official style guides for the MLA, APA, and Chicago formats. 

The MLA's Mission

The official website for each style is always the best place to go for the most accurate information on its usage, and the MLA's site is no exception. This link will lead you to a wealth of information on the MLA's history, strategic goals, and achievements. 

"The Lying Art of Historical Fiction" (The Guardian)

Although not directly about citations, this 2010 piece from The Guardian deals with the complex related question of misrepresenting historical information, asking whether historical inaccuracies can ever be "constructive lies."

"Tutorial: Citing Government Documents" (Univ. of North Texas)

This webpage, published by the University of North Texas, deals with the sometimes complex issue of citing government documents. Although this topic may not be a primary issue, in some cases it could add helpful nuance to an assignment.