A Comprehensive Guide to Citation Styles: APA, MLA, and IEEE Explained

For students, researchers, and writers, correctly citing sources is a fundamental requirement of academic integrity. Citation not only acknowledges the work of others but also allows readers to trace your research and builds your credibility. However, with various citation styles available, choosing and correctly implementing the right one can be confusing.
This guide provides a detailed explanation of the three most prevalent citation formats—APA, MLA, and IEEE—outlining their core principles, typical use cases, and providing clear examples to help you master academic writing.

1. APA Style: The Standard in Social Sciences
APA (American Psychological Association) style is the go-to format for publications, papers, and books in the social and behavioral sciences. It is widely used in fields like Psychology, Education, Business, and Communications. The latest edition is the APA 7th Edition.
APA emphasizes the recency of research, which is why the publication date is placed prominently in citations.
Key Features of APA 7th Edition:

In-Text Citations: Uses the author-date format.
- Parenthetical: (Smith, 2020)
- Narrative: Smith (2020) argued that...
- With page number for direct quotes: (Smith, 2020, p. 15)
Reference List:
Titled "References" and alphabetized by the author's last name.
Uses a hanging indent for each entry.
Journal titles are written in title case and italicized.
Book and article titles are written in sentence case (only the first word and proper nouns are capitalized).

Common APA Citation Examples:

Journal Article:

Author, A. A., & Author, B. B. (2020). Title of the article in sentence case. Title of Periodical in Title Case and Italics, volume number(issue number), pages. https://doi.org/xxxx

Book:

Author, A. A. (2021). Title of work: Capital letter also for subtitle. Publisher Name.

Website:

Author, A. A., or Group Name. (Year, Month Day). Title of content in sentence case and italics. Site Name. https://xxxxx

2. MLA Style: The Heart of the Humanities
MLA (Modern Language Association) style is the dominant format in the humanities, including fields like Literature, Arts, Philosophy, and Foreign Languages. It focuses on authorship and the source's medium. The current version is the MLA 9th Edition.
MLA uses a flexible "container" system, where sources are seen as containers (e.g., a journal is a container for an article) that hold information.
Key Features of MLA 9th Edition:

In-Text Citations: Uses the author-page number format.
- (Smith 74)
- According to Smith, ... (74).
Works Cited Page:
Titled "Works Cited" and alphabetized by the author's last name.
Uses a hanging indent.
All major words in titles (books, articles, journals) are capitalized (Title Case).
Titles of longer works (books, journals) are italicized; titles of shorter works (articles, chapters) are enclosed in quotation marks.

Common MLA Citation Examples:

Journal Article:

Author's Last Name, First Name. "Title of the Article in Title Case." Title of Journal, vol. number, no. issue number, Publication Date, pp. page range. Database Name (if applicable), doi:xxxx or URL.

Book:

Author's Last Name, First Name. Title of Book in Title Case. Publisher, Publication Year.

Website:

Author's Last Name, First Name, or Organization Name. "Title of the Webpage." Name of the Website, Day Month Year, URL.

3. IEEE Style: The Foundation of Technical Fields
IEEE (Institute of Electrical and Electronics Engineers) style is the standard for technical documents, particularly in engineering, computer science, and information technology.
IEEE uses a numeric system. Sources are numbered in the order they appear in the text, and the full citation for that number is listed in the reference list. This method is efficient for papers with many equations and data points.
Key Features of IEEE Style:

In-Text Citations: Uses bracketed numbers.
- ...as demonstrated in [1].
- The theory was first proposed by Johnson [2].
- For more details, see [3, pp. 5-10].
Reference List:
Titled "References" and ordered numerically (not alphabetically).
The bracketed number precedes each reference entry.
Author names are formatted as First Initial. Last Name (e.g., J. Smith).
Titles of articles are in sentence case and enclosed in quotation marks.
Titles of journals and books are in title case and italicized.

Common IEEE Citation Examples:

Journal Article:

[1] A. A. Author and B. B. Author, "Title of article in sentence case," Abbreviated Title of Journal in Title Case, vol. #, no. #, pp. xxx-xxx, Month, year.

Book:

[2] C. C. Author, Title of Book in Title Case. City of Publication, State/Country: Publisher, year.

Website:

[3] D. D. Author. (Year, Month Day). Title of Post or Page. Site Name. Accessed: Month, Day, Year. [Online]. Available: https://xxxxx

Summary: Which Style Should You Use?

Feature	APA (7th Ed.)	MLA (9th Ed.)	IEEE
Primary Fields	Social Sciences, Education, Business	Humanities (Literature, Arts)	Engineering, Computer Science, IT
In-Text Citation	(Author, Year)	(Author Page)	[1]
Reference List Title	References	Works Cited	References
Reference Order	Alphabetical by author	Alphabetical by author	Numerical by order of appearance
Article Titles	Sentence case	"Title Case in Quotes"	"Sentence case in quotes"
Book/Journal Titles	Italicized, Title Case	Italicized, Title Case	Italicized, Title Case

Conclusion
Choosing the correct citation style is not just about following rules; it's about speaking the academic language of your chosen field. Always confirm the required format with your professor, publisher, or conference guidelines. By understanding the core principles of APA, MLA, and IEEE, you can present your research professionally and ethically, ensuring your work stands on a strong foundation of scholarly integrity.