Chicago citation style

A guide to citing sources using the Chicago Manual of Style, 17th edition

General rules

In Chicago Author-Date citation Style, when information is quoted or referred to in your paper, a citation in parenthesis is given to identify the source of the quotation or information. The in-text citation typically includes the author's last name, the date, and the page number, if the source has one (15.7).

Sample in-text citation:

"The spread of electric lights through rural Newfoundland was destined to be slow and uneven" (O'Flaherty 2005, 218).

Citing works without an author

If a source has no author, begin your in-text citation with the title instead. If the title is 5 words or longer, use a short form of the title. Short titles should be 1-4 keywords from the original title, leaving out "A" or "The" at the beginning. Titles should be italicized or enclosed in quotation marks, depending on how they are referenced in your reference list (15.34).

Sample in-text citations:

(Around the World 1909)

("Aristotle's Protrepticus" 1965, 42)

Citing works without a date

If a source has no date, use "n.d." to indicate no date. Unlike in-text citations with numerical dates, "n.d." should be preceded by a comma so that the reader does not interpret it as being part of the author's name (15.44).

Sample in-text citation:

(Nano, n.d.)

Citing works without page numbers

If a text source has no page numbers, identify the location of a citation or quotation by adding a description like a paragraph number, heading, or section description (15.23). These descriptive terms are typically abbreviated—a list of scholarly abbreviations can be found in section 10.42.

Sample in-text citations:

(Claussen 2015, para. 2.15)

(Johnson 1979, sec. 24)

Citing works with multiple authors

Works with 2-3 authors

Include the last names of all authors, separated using commas with the word and before the final author's name (15.9).

Sample in-text citations:

(Ward and Burns 2007, 99-100)

(Heatherton, Fitzgilroy, and Hsu 2008)

Works with 4 or more authors

Include the last name of the first author only, followed by et al. (15.29).

Sample in-text citation:

(Barnes et al. 2008, 118-19)