APA, MLA, Chicago: Citation Format Guide

Three major citation systems dominate academic writing: APA (American Psychological Association), MLA (Modern Language Association), and Chicago. Each serves a different set of disciplines and reflects different priorities about what information matters most when attributing sources. Getting the wrong one, or mixing elements of multiple systems, is one of the most common reasons academic papers lose marks.

Which Style to Use and When

The choice of citation style is usually dictated by your discipline or your professor. As a general rule:

• APA 7th Edition - Social sciences, psychology, education, nursing, business. Emphasizes the date of publication because currency matters in these fields.
• MLA 9th Edition - Humanities: literature, languages, philosophy, arts. Emphasizes the author and page number because the text itself is the primary object of study.
• Chicago 17th Edition (Author-Date) - History, social sciences, some sciences. Footnote-based system that allows for extensive commentary alongside citations.
• Chicago 17th Edition (Notes-Bibliography) - History, art history, some humanities. Uses footnotes for citations and a Bibliography at the end.

When in doubt, ask your professor or journal. Submitting in the wrong style is treated the same as formatting errors, and fixing it manually across a 30-page paper is extremely time-consuming.

APA 7th Edition

In-Text Citations

APA uses an author-date parenthetical system. The basic format is (Author Last Name, Year). Include a page number only for direct quotes:

• Paraphrase: (Smith, 2022)
• Direct quote: (Smith, 2022, p. 45)
• Two authors: (Smith & Jones, 2022)
• Three or more authors: (Smith et al., 2022)
• Corporate author, long: (American Psychological Association [APA], 2020) first citation; (APA, 2020) thereafter
• No author: Use first few words of title in italics: ("Document Formatting," 2022)

Reference List Format

APA calls the bibliography a "References" page. Key rules:

• Title it "References" (centered, bold, not italicized)
• Double-spaced, hanging indent for each entry (0.5 inch)
• Alphabetical by author's last name
• If multiple works by same author, order by publication year (oldest first)

Journal article format:

Smith, J. A., & Jones, B. C. (2022). The impact of formatting on readability. Journal of Document Science, 14(3), 122-140. https://doi.org/10.xxxx/xxxx

Book format:

Smith, J. A. (2021). Document intelligence: A modern approach (2nd ed.). Academic Press.

Website format:

Smith, J. A. (2023, March 15). How to format your documents. Retrieved from https://example.com/formatting

Key APA 7 Changes from APA 6

• Running heads are no longer required for student papers
• Up to 20 authors can now be listed before using "et al." (was 6)
• DOIs are now formatted as hyperlinks: https://doi.org/xxxx
• Place of publication is no longer required for books
• "Retrieved from" is no longer needed before URLs unless the content changes (like Wikipedia)

MLA 9th Edition

In-Text Citations

MLA uses author-page parenthetical citations. The date is not part of the in-text citation:

• Paraphrase: (Smith 45)
• Direct quote: (Smith 45)
• No author: (Short Title 45)
• Two authors: (Smith and Jones 45)
• Three or more: (Smith et al. 45)
• Named in sentence: "Smith argues that formatting matters (45)"

Works Cited Format

MLA calls the bibliography "Works Cited." It uses a flexible "container" model introduced in MLA 8:

Journal article format:

Smith, John A. "The Impact of Formatting on Readability." Journal of Document Science, vol. 14, no. 3, 2022, pp. 122-140.

Book format:

Smith, John A. Document Intelligence: A Modern Approach. 2nd ed., Academic Press, 2021.

Website format:

Smith, John A. "How to Format Your Documents." Example Site, 15 Mar. 2023, www.example.com/formatting. Accessed 5 Apr. 2026.

Key MLA 9 Rules

• Use double quotation marks for article and chapter titles, italics for books, journals, and websites
• MLA 9 explicitly includes DOIs and URLs for digital sources
• Access dates are now optional but recommended for frequently changing content
• Use first names in full (John Smith, not J. Smith) in Works Cited

Chicago 17th Edition

Two Systems Within Chicago

Chicago is actually two systems. Which you use depends on your discipline:

• Notes-Bibliography (NB): Used in history, art history, and some humanities. Uses footnotes or endnotes for citations, plus a Bibliography at the end.
• Author-Date (AD): Used in social sciences and some sciences. Similar to APA, uses parenthetical in-text citations and a References list.

Notes-Bibliography In-Text and Footnote Format

In Chicago NB, citations appear as numbered superscripts in the text, with full citations in footnotes at the bottom of the page. The footnote format for a first citation of a journal article:

1. John A. Smith, "The Impact of Formatting on Readability," Journal of Document Science 14, no. 3 (2022): 130, https://doi.org/10.xxxx/xxxx.

Subsequent citations of the same source use a shortened form:

3. Smith, "Impact of Formatting," 135.

Bibliography Format

Smith, John A. "The Impact of Formatting on Readability." Journal of Document Science 14, no. 3 (2022): 122-140. https://doi.org/10.xxxx/xxxx.

Note that bibliography entries are alphabetical and use last-name-first for the first author, while footnotes use normal order.

Side-by-Side Comparison: Same Source, Three Styles

Source: A journal article by Mary Johnson and Robert Lee published in 2023 in "Science of Documents," volume 8, issue 2, pages 45-67.

Common Citation Mistakes (And How to Avoid Them)

• Mixing styles: Using APA author-date in text but MLA Works Cited format in the bibliography. Pick one and be consistent throughout.
• Missing hanging indent: All three styles require a hanging indent (first line flush left, subsequent lines indented 0.5 inch) in the reference/bibliography list.
• Wrong punctuation for et al.: In APA 7, it's "Smith et al." (no comma before et al.). In Chicago, it's "Smith et al." In MLA, it's "Smith et al." but only for 3+ authors. Always include a period after "al."
• DOIs vs. URLs: Always prefer a DOI when available. DOIs are permanent; URLs break.
• Inconsistent capitalization: APA uses sentence case for article titles (only capitalize the first word and proper nouns). MLA uses title case (capitalize major words). Chicago uses title case in most contexts.

Automating Citation Fixes

Manually checking every citation in a 50-source bibliography is error-prone and time-consuming. The FixMyDocs Academic Mode workspace can identify citation style inconsistencies, fix APA 7th, MLA 9th, and Chicago 17th formatting errors, improve academic tone, and restructure papers to match standard section conventions (Abstract, Introduction, Literature Review, Methodology, Results, Discussion, Conclusion).

Upload your draft and specify your target citation style. The AI identifies every citation in the text, checks it against the style rules, and outputs a corrected version with a clean reference list. This is particularly useful when consolidating a bibliography assembled by multiple coauthors using different tools.