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Cite Your Sources: Chicago Author-Date System

What is chicago author-date system?

  • Uses the author and year in parentheses as the in-text citation and uses a reference list.
  • Preferred by many writers in the sciences and social sciences.
  • Information in the guide is based on the 17th edition of the Chicago Manual of Style

How do I format my in-text citations?

  • Author’s name and the year of publication enclosed in parentheses. 
    • (Smith 2010).
  • You do not need to repeat any elements that are already in your sentence.
    • As Novak and Gowin (1984) point out, children find concept maps useful for learning.
  • When referring to a specific section, include the page number.
    • Put simply, "to evaluate, we must have a clear notion of value" (Novak and Gowin 1984, 109)

How do I format my reference list?

  • The reference list appears at the end of the paper.  
  • The title should be References or Works Cited.
  • It should include only sources that you cite in your assignment.
  • List your sources alphabetically by author's last name. First author should be listed by Last name, First name.
  • Entries are single spaced.
  • Use a hanging indent after the first line of the entry.
  • The reference list entry is structured similarly to the Bibliography (in Chicago Notes and Bibliography system), except that the publication date is the second element, following the author's name.

Book, one author

In-text citation:

… was tested (Morton 2001).

Reference List:

Last Name, First Name. Date. Title. Place of Publication: Publisher.

Morton, Desmond. 2001. A Short History of Canada. Toronto: McClelland & Stuart.

An article in a journal or periodical (print)

In-text citation:

...(Flint and Lolcama 1986).

Reference List:

Last Name, First Name. Date. “Article Title.” Journal Title volume #(no. #): page range.

Flint, Jean-Jacques, and J. Lolcama. 1986. “Buried Ancestral Drainage between Lakes Erie and Ontario.” Geological Society of America Bulletin 97(1): 221-32.

An article in a journal or periodical (Online)

In-text citation:

... (Hom Carey 2004).

Reference List:

Last Name, First Name. Date. “Article Title.” Journal Title volume # (no. #): page range. Accessed date. doi/url.

Hom Carey, Stephanie. 2004. “The Tourist Moment.” Annals of Tourism Research 31(1): 121-34. doi:10:48903243/342890.

  • Accessed date is usually considered unnecessary unless no date of publication or revision can be determined from the source. The DOI is preferred over the URL.

Part of an edited work or collection

In-text citation:

...(Veal and Hudson 2009).

Reference List:

Last Name, First Name. Date. "Title of Chapter." In Title of Book, edited by 1 Editor First Name Last Name and 2 Editor First Name Last Name, pp-pp. Place of Publication: Publisher.

Veal, L. Ramon, and Sally Ann Hudson. 2009. "Direct and Indirect Measures for Large-Scale Evaluation of Writing." In Assessing Writing: A Critical Sourcebook, edited by Brian Huot and Peggy O'Neill, 13-17. Boston: Bedford/St.Martin's.

Looking for other examples?

Generative AI (e.g. ChatGPT)

Follow your professor’s instructions when considering the use of generative AI tools (such as ChatGPT).  If you have permission to use these programs, please cite the AI content (ideas and/or words) you incorporate into your text.  Your professor might provide instructions for citing outputs from generative AI sources. If this is the case, please follow the instructions provided.

If you have been asked to use the Chicago Manual of Style (CMOS) Author-Date system, instructions have been provided on this Q&A page.  Please read carefully because instructions for Notes and Bibliography as well as Author-Date are explained in the same text.  The Writing Services team will continue to monitor announcements from CMOS for further updates.

Resources to help with writing

Guide: Plagiarism and Academic IntegrityGuide: Cite Your SourcesLink to Guide: Write clearly: Grammar

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