The Ultimate Guide to Citing Sources: MLA, APA, and Chicago Styles Explained

Academic writing requires you to build your arguments on the work of others, and properly citing your sources is the foundation of academic integrity. However, the different citation styles—MLA, APA, Chicago—can be confusing for students. Which one should you use? What's the difference between an in-text citation and a full citation? This guide will demystify the three most common citation styles, explain when to use each one, and provide clear examples to help you cite your sources correctly and confidently.

Why Do We Cite Sources?

Before diving into the styles, it's important to understand why citation is so critical. We cite sources to:

• Avoid Plagiarism: To give credit to the original authors for their ideas and words.
• Lend Credibility: To show that your arguments are supported by reliable research.
• Help Your Reader: To allow your reader to find the original sources you used.

1. MLA Style (Modern Language Association)

When to use it: MLA is most commonly used in the humanities, including English, literature, foreign languages, and philosophy.

Key Features: MLA uses parenthetical in-text citations that feature the author's last name and the page number. The full list of sources at the end of the paper is called the "Works Cited" page.

MLA Examples:

• In-Text Citation: Wordsworth stated that Romantic poetry was marked by a "spontaneous overflow of powerful feelings" (263).
• Works Cited (Book):
  Wordsworth, William. Lyrical Ballads. Oxford University Press, 1967.
• Works Cited (Website):
  Lundman, Susan. "How to Make Vegetarian Chili." Allrecipes, 18 Mar. 2020, www.allrecipes.com/recipe/72508/vegetarian-chili/.

2. APA Style (American Psychological Association)

When to use it: APA is widely used in the social sciences, such as psychology, sociology, education, and communications, as well as in business and nursing.

Key Features: APA emphasizes the date of a source, as currency is important in scientific fields. In-text citations include the author's last name and the year of publication. The full list of sources is called the "References" page.

APA Examples:

• In-Text Citation: Research shows that cognitive-behavioral therapy is an effective treatment for anxiety (Beck, 2011).
• References (Book):
  Beck, J. S. (2011). Cognitive behavior therapy: Basics and beyond (2nd ed.). The Guilford Press.
• References (Journal Article):
  Scruton, R. (1996). The eclipse of listening. The New Criterion, 15(3), 5–13.

3. Chicago Style (The Chicago Manual of Style)

When to use it: Chicago style is most often used in history, but also in many other fields in the humanities and social sciences. It is the most flexible style and offers two different systems.

Key Features:
a) Notes and Bibliography: This system uses numbered footnotes or endnotes for in-text citations and a "Bibliography" at the end. This is the most common system in the humanities.
b) Author-Date: This system is very similar to APA, using parenthetical in-text citations with the author's name and year. It is more common in the sciences.

Chicago Examples (Notes and Bibliography):

• In-Text Citation (via Footnote): At the end of a sentence containing a source, you would insert a superscript number.¹
• Footnote at Bottom of Page:
  ¹ Michael Pollan, The Omnivore's Dilemma: A Natural History of Four Meals (New York: Penguin, 2006), 99–100.
• Bibliography (Full Citation):
  Pollan, Michael. The Omnivore's Dilemma: A Natural History of Four Meals. New York: Penguin, 2006.

Conclusion: Consistency is Key

Regardless of which style you are asked to use, the most important rule is consistency. Always follow the specific guidelines for the style you have chosen throughout your entire paper. When in doubt, consult a style guide like the Purdue Online Writing Lab (OWL) or ask your instructor for clarification. Proper citation is a hallmark of careful and credible academic work.