Rules

In the author-date system, sources are briefly cited in the text, usually in parentheses, by author’s last name and year of publication. Each in-text citation matches up with an entry in a reference list, where full bibliographic information is provided. Because it credits researchers by name directly in the text while at the same time emphasizing the date of each source, the author-date system is preferred by many in the sciences and social sciences.

Aside from the use of numbered notes (Chicago A) versus parenthetical references in the text (Chicago B), the two systems share the same style for authors’ names, titles of works, and other cited components. Placement of year of the publication differs, see CMOS 14.1.

Specifics for using Chicago B for in-text references

• When using secondary references, name both sources in-text: Johnson and Peters’ studies (1939, cited in Wagner 1982, 207)
• To distinguish multiple publications by the same author published the same year, write a, b, c, etc. after the year: Hansen (1988a) and Hansen (1988b) in both the citation and reference list.
• When a work has no identifiable author, write the title.
• Publications with many authors who are cited more than once:
  • 2 or 3 authors: write both authors’ names every time you cite them. Example: (Furseth and Everett 1997), (Reve, Lensberg and Grønhaug 1992)
  • 4 or more authors: only write the surname of the first author followed by et al. Example: Cheng et al. (2004)