15 Two or More Works – Same Parentheses

Several Studies

When an author or authors have published a number of articles with the same publication date, assign suffixes a, b, c, d, and so on, to differentiate them. Make sure to repeat the year.

(Derryberry & Reed, 2005a, 2005b, in press-a; Rothbart, 2003a, 2003b)

In the reference list you should see three entries for Derryberry and Reed, and two for Rothbart. Items in the reference list will be ordered alphabetically according to title of the article, chapter, or complete work.

List Authors Alphabetically

Several studies (Miller, 1999; Shafranske & Mahoney, 1998)

Citations From the Same Author But In Different Years

Past research (Gogel, 1990, 2006, in-press)[1]

(American Psychological Association,  2010, pp. 177-178)


  1. in-press indicates that an article has been accepted for publication but has not been published yet (American Psychological Association, p. 185)

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