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About Chicago: Author-Date
The Chicago Manual of Style Author-Date system is used by scholars in the social sciences and sciences. For arts, history, and humanities, see the Notes/Bibliography system.
Citing sources in this style consists of two parts:
- An in-text citation
- A reference list
The in-text citation points the reader to the full information about the source found in the reference list.
See How to Format In-Text Citations, How to Format the Reference List, and the examples of types of sources in the left navigation for further details.
How to Format In-Text Citations
An in-text citation provides your reader with two pieces of information:
- The the last name of the author(s) used in the corresponding reference list entry
- The year the work was published
Standard Formatting of the In-Text Citation
For more detailed information see Chicago Manual of Style, 15.21-15.31.
- Enclose the author's last name and the year of publication in parentheses with no intervening punctuation.
- For no author, see the "How do I deal with ____?" section.
- For two to three authors, include the last names of authors using commas and and
(Smith, Lee, and Alvarez 2016)
- For four or more authors, include the last name of the first author and et al.
(Smith et al. 2016)
- When editors, translators, or compilers are used as the author, do not include their role (trans., ed., comp.) in the in-text citation.
- When the reference list has works by authors with same last name, include their first initial in the in-text citation
(B. Smith 2016)
(J. Smith 2009)
- If an author has published multiple works in the same year, alphabetize the titles in the reference list and then add a, b,c, etc. to the year
- To cite specific page(s), add a comma and the page number(s)
(Smith 2016, 21-23)
- If the author's name appears in the sentence, do not include the name again in the parentheses
Smith (2016) indicates that good citation practices are important.
- To cite more than one reference in a single in-text citation, separate the references by semicolons. If the works are by the same author, use just the year and separate with a comma. See CMOS 15.30 for details.
(Smith 2016; Lee 2015)
(Smith 2016, 2013; Lee 2015)
How to Format the Reference List
General Formatting of the Reference List
For more detailed information see Chicago Manual of Style, 15.10-15.20
The reference list provides the full details of the items you have cited in your paper. Here are some general features of the reference list:
- Usually titled References or Works Cited
- Entries begin with author(s) and date of work; other required elements depend on the type of source. See examples in the left navigation.
- Entries are arranged alphabetically by the last name of the first author
- alphabetize using the letter-by-letter system, in which an entry for “Fernández, Angelines” would come before the entry for “Fernán Gómez, Fernando” (d in "Fernández" comes before G in "Gómez")
- If there is no author, use the first word of the title of the work (excluding The, A, An).
- Single-author entries precede multiauthor entries beginning with the same name.
- Multiple works by the same author(s) are arranged chronologically, and the 3-em dash replaces the name for the second and subsequent entries.
Du Bois, W. E. B. 1898. "The Study of the Negro Problems." Annals of the American Academy of Political and Social Science 11 (January): 1-23. http://www.jstor.org/stable/1009474.
———. 1903. The Souls of Black Folk: Essays and Sketches. Chicago: A. C. McClurg.
———. 1947. The World and Africa: An Inquiry into the Part Which Africa Has Played in World History. New York: Viking.
- Multiple works by same author in same year are arranged alphabetically by title, and then a, b, c, etc. is added to the year to help make each entry unique for the in-text citation.
Olney, William W. 2015a. "Impact of Corruption on Firm-Level Export Decisions." Economic Inquiry 54 (2): 1105–27.
Olney, William W. 2015b. "Remittances and the Wage Impact of Immigration." Journal of Human Resources 50 (3): 694-727.
How do I deal with ___?
Missing citation elements
- If no personal author is listed, determine whether an organization is responsible for the content. If so, use that organization's name as the author in the reference list and in-text citation. (CMOS, 15.36)
(World Bank 2011)
World Bank. 2011. Poverty and Social Exclusion in India. Washington, DC: World Bank.
- If a newspaper article is unsigned, use the newspaper title as the author. (CMOS, 15.49)
(New York Times 1912)
New York Times. 1912. "Titanic Sails To-Day." April 10, 1912.
- If the author is unknown, start the reference list entry with the title. For the in-text citation, use the title, which can be shortened as long as the first word matches the reference list entry. (CMOS, 15.34)
- Date: If there is no publication or last modified date, use n.d. (CMOS, 15.44 and 15.50)
(Human Rights Campaign, n.d.)
Human Rights Campaign. n.d. "Maps of State Laws and Policies." Accessed April 25, 2019. http://www.hrc.org/state_maps.
- Page numbers: For unpaginated works, such as online resources, include a descriptive phrase using one of the divisions used in the work (chapter, paragraph number, section heading, etc.) in the in-text citation. If the work is short, such locators may not be necessary. (CMOS, 15.23)
(Library of Congress, n.d., under "Slave Narratives and the New Debate about Slavery")
Library of Congress. n.d. "Slave Narratives from Slavery to the Great Depression." An Introduction to the WPA Slave Narratives. Accessed June 27, 2019. https://www.loc.gov/collections/slave-narratives-from-the-federal-writers-project-1936-to-1938/articles-and-essays/introduction-to-the-wpa-slave-narratives/slave-narratives-from-slavery-to-the-great-depression/.
- Place: Use n.p. if it is unknown. If it can be surmised, put in brackets with a question mark. (CMOS, 14.132)
- Publisher: If not listed on the title page or copyright page, use "self-published" or "printed by author." (CMOS, 14.137)
More than one author
- List authors in order they appear on title page
- In the reference list, invert the first author's name only and place a comma before and after the first name
- Use the word "and," not an ampersand (&)
- For works with 4-10 authors, list all names in the reference list, but only use the first author's name followed by et al. in the in-text citation.
- For works with more than 10 authors, only include the first 7 authors and et al. in the reference list
(CMOS, 15.9, 15.16, 15.29, 14.76)
(Geis and Bunn 1997, 17)
(Chih-Hung Ko et al. 2009, 600)
Geis, Gilbert, and Ivan Bunn. 1997. A Trial of Witches: a Seventeenth-Century Witchcraft Prosecution. London: Routledge.
Ko, Chih-Hung, Ju-Yu Yen, Shu-Chun Liu, Chi-Fen Huang, and Cheng-Fang Yen. 2009. "The Associations between Aggressive Behaviors and Internet Addiction and Online Activities in Adolescents." Journal of Adolescent Health 44 (6): 598-605.
Using a source quoted in a secondary source
It is always better to consult the original source, but if it cannot be obtained, give information about the original source in the running text and include "quoted in" in your in-text citation for the secondary source. Include only the secondary source in your reference list. (CMOS, 15.56)
In his 1844 book Thoughts on the Proposed Annexation of Texas to the United States, Theodore Sedgwick opines "The annexation of Texas instead of strengthening the Union, weakens it" (quoted in Rathbun 2001, 479).
Rathbun, Lyon. 2001. "The Debate over Annexing Texas and the Emergence of Manifest Destiny." Rhetoric & Public Affairs 4 (3): 459-493.
Examples: Books, Chapters
Examples: Websites, Blogs, Social Media
Examples: Music, Film, TV, Images
Examples: Government Documents
Examples: Unpublished / Archival
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Chicago Manual of Style Online
Searchable online version of the most recent edition of this style guide from the University of Chicago Press, together with the Chicago Style Q&A.
Chicago Style Q&A
Provides official answers to questions submitted by users of the Chicago Manual of Style.
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