Any time you quote, paraphrase, summarize, or reference a source, you must cite that source in a parenthetical note or a footnote and append a bibliography, which, depending on the discipline, may be called “Works Cited” or “References.”
All citations share some basic components, including the title of the work being referred to, the name of the work’s author(s), the publisher, and the date of publication. Beyond these general requirements, styles of citation vary by discipline and by professor’s preference. In the humanities, the most commonly accepted citation style is that of the Modern Language Association (MLA). In the social sciences, the American Psychological Association (APA) style is widely used. Historians typically employ the footnote style described in The Chicago Manual of Style (CMS). Each scientific discipline has its own protocols and formats, usually available in a style manual produced by the discipline’s scholarly organization. You’ll see that many academic disciplines encourage the use of in-text parenthetical citations rather than footnotes.
Once you join a department as a concentrator and begin your junior year work, the department should provide you with information about expected citation formats and practices in the discipline. Often, individual professors will provide you with information about their preferred citation format.
The examples that follow employ four different citation styles. For the specifics of each style, you should consult an official style manual, because the rules for citation vary greatly for different kinds of sources. For example, books are cited differently from articles, which are cited differently from e-mail correspondence. You’ll need to consult a style manual to determine the proper format for each source type. (A list of recommended style manuals may be found at the end of this section.)
Example 1: Literary Studies (MLA).
The MLA requires a parenthetical citation in the body of the text that corresponds to an entry in the Works Cited at the end. A citation for a quotation from a book in the MLA style is formatted this way:
As Frank Lentricchia argues, The Waste Land should not be understood as a logical sequence of events but as “an intellectual and emotional complex grasped in an instant of time” (194).
The parenthetical citation “(194)” refers to a page number from a book by Frank Lentricchia. Publication information about the book would be found in the Works Cited, where it would be formatted this way:
Lentricchia, Frank. Modernist Quartet. New York: Cambridge University Press, 1994.
Example 2: Psychology (APA).
The APA also requires parenthetical citations in the body of the text, though these citations typically include the author and the date. A citation for a summary of an article in the APA style is formatted this way:
Studies that examine links between cardiovascular and mental activity must understand that cardiovascular activity itself comprises a suite of variables (Van Roon, Mulder, Althaus, and Mulder, 2004).
The parenthetical citation “(Van Roon, Mulder, Althaus, and Mulder, 2004)” refers to an article by the four listed coauthors. Publication information about the article would be found in the References, where it would be formatted this way:
Van Roon, A., Mulder, L., Althaus, M., and Mulder, G. (2004). Introducing a baroflex model for studying cardiovascular effects of mental workload. Psychophysiology, 41, 961–981.
Example 3: History (CMS).
CMS, or “Chicago,” is a style in which citations are presented in footnotes. A citation for a quotation from an article in the Chicago style is formatted this way:
Nineteenth-century bohemians were more dependent on mainstream culture than might at first appear. As one scholar puts it, “Bohemia”s self-designated types always existed in symbiotic relation to bourgeois culture rather than in opposition to it.”1
The footnote “1” would refer to a note at the bottom of the page containing full publication information and formatted this way:
1. Christine Stansell, American Moderns: Bohemian New York and the Creation of a New Century (New York: Henry Holt and Co., 2000), 18.
Example 4: Biology.
Citation styles in math, science, and engineering tend to vary from journal to journal. Following a quotation or a reference to the text, the author might name the source, or might use a superscript number such as 1 or a parenthetical number such as (1), to indicate the number of the article in the final list of references. The journal Nature Genetics uses the following format for articles, and the references are listed numerically rather than alphabetically:
13. Herron, B. J. et al. Efficient generation and mapping of recessive developmental mutations using ENU mutagenesis. Nat. Genet. 30, 185–189 (2002).
Because of the variety of citation styles for math, science, and engineering, you should consult your professor about their preferences and expectations.
An electronic source is any source that exists primarily in electronic form and is accessed primarily through electronic means. Websites, online periodicals, online books, e-mails and postings, and even CD-ROMs are all forms of electronic sources. But be careful: not all materials found through electronic means are necessarily electronic sources. For example, if a PDF of an article you found through a database on the library’s website was originally published in a printed journal, then the article doesn’t qualify as an electronic source. In short, there’s a difference between electronic sources and sources that are accessed electronically.
When citing an online source, your citation should contain the following elements:
- the author or editor (if available),
- the title of the text (if different from the name of the website),
- the name of the website,
- the name of the site’s sponsor or associated institution or organization,
- the date you accessed the site,
- the electronic address (URL).
For example, a short work posted on a website would be formatted in MLA style as follows:
McCort, Dennis. “Kafka and the Coincidence of Opposites.” Romantic Circles Praxis Series: Romanticism and Buddhism. February 2007. Romantic Circles. 21 April 2008. ≺ http://www.rc.umd.edu/praxis/buddhism/mccort/mccort.html ≻
This citation includes not only the author’s name and the work’s title, but also other important information, including the date of the work’s publication on the site (February 2007) and the date the website was accessed (21 April 2008).
The published guides of the MLA, APA, and Chicago styles include detailed descriptions of how to cite most electronic sources. As explained earlier on this website, the emerging nature of this new technology means that conventions are forming quickly, and the variations among citation styles vary considerably. Be sure to look up the appropriate form of citation and to consult your professor about any points of confusion.
Recommended Style Manuals
For complete coverage of MLA, APA, and Chicago citation styles, you should obtain the most recent edition of each style’s official manual: MLA Handbook for Writers of Research Papers (8th edition, 2016), the Publication Manual of the American Psychological Association (6th edition, 2009), and The Chicago Manual of Style (16th edition, 2010). For an online guide to these styles, visit the Library website, at library.princeton.edu/help/citing-sources. A good commercially published guide is A Pocket Style Manual, by Diana Hacker and Nancy Sommers (2014), which includes brief but substantial overviews of the MLA, APA, and Chicago styles.
This LibGuide was designed to provide you with assistance in citing your sources when writing an academic paper.
There are different styles which format the information differently. In each tab, you will find descriptions of each citation style featured in this guide along with links to online resources for citing and a few examples.
What is a citation and citation style?
A citation is a way of giving credit to individuals for their creative and intellectual works that you utilized to support your research. It can also be used to locate particular sources and combat plagiarism. Typically, a citation can include the author's name, date, location of the publishing company, journal title, or DOI (Digital Object Identifer).
A citation style dictates the information necessary for a citation and how the information is ordered, as well as punctuation and other formatting.
How to do I choose a citation style?
There are many different ways of citing resources from your research. The citation style sometimes depends on the academic discipline involved. For example:
- APA (American Psychological Association) is used by Education, Psychology, and Sciences
- MLA (Modern Language Association) style is used by the Humanities
- Chicago/Turabian style is generally used by Business, History, and the Fine Arts
*You will need to consult with your professor to determine what is required in your specific course.
Click the links below to find descriptions of each style along with a sample of major in-text and bibliographic citations, links to books in PITTCat+, online citation manuals, and other free online resources.