Chicago Style Guide: In-text Citations

In the Author Date system, an in-text citation should appear in parentheses at the end of the sentence.  It should feature the first two elements from the reference list: the author’s name, and the date of publication.  If the author’s name appears in the text, simply put the date in parentheses right after it.  Page numbers may be added for clarity; cite only the page you are referencing.  Do not include additional editor or translator names.

(Smith 2016, 347)

(Grazer and Fishman, 2015)

If there are three or fewer authors, list them all:

(Keng, Lin, and Orazem, 2017)

If there are four or more authors, type only the first name and then use et al.:

(Bay et al. 2017, 465)

If the paper cites more than one source from the same author published in the same year, differentiate by putting letters after the date in both the citation and the reference.

(Chomsky, 1996a)

If your quotation takes up over five lines or 100 words, it should be set off in a block:

The U.S. government's spending power and habits with respect to contractor hiring decisions have a great impact on people around the globe.  For this reason, it would be prudent for the United States to ensure that its over $350 billion annual procurement spending budget goes towards protecting human rights around the world rather than to companies with a history of abuse allegations. (Herbst, 2018)

An email, tweet, or other personal communication is only cited in-text; it does not get a full citation in the reference list.

(Peter Jones, Facebook message to author, October 1, 2018)