Overlapping of References in APA Format

Same Author

• The Purdue Online Writing Lab explains same author guidelines. If you need to document one author who has written different articles in different years, list the earlier date first on the reference page. For example, Ross, S. A. (2007) will precede Ross, S. A. (2010). The in-text citations (Ross, 2007) and (Ross, 2010) clearly differentiate the two sources.

Same Author/Year

• If you reference an author who has written two articles within the same year, use the letters "a" and "b" to identify each, and further alphabetize by the article title. On the reference page, "Spengler, J. L. (2004a). Affective domain" will appear before "Spengler, J. L.(2004b). Emotional trauma." In-text citations take this form: (Spengler, 2004a) or (Spengler, 2004b). (Ref. 2)

Same Last Name

• When you cite different authors with the same surname on the reference page, simply alphabetize by first initials: Madsen, R. (2007) follows Madsen, M. (2007). In-text citations require the authors' initials: (R. Madsen, 2007) or (M. Madsen, 2007).

Single and Group

• Sometimes, your reference page includes articles by a single author who has written additional articles with a group. The single-author entry "Roberts, B. J. (2010)" will precede a group article where Roberts appears as the lead author: "Roberts, B.J., Ross, S. A., & Spengler, J. L. (2008)." (Ignore the date when following this guideline.) In-text citations differentiate these sources: (Roberts, 2010) and (Roberts, Ross, & Spengler, 2008).

Group Entries

• When you have two group entries with the same lead author but different additional authors, arrange them by the second author, not the date. "Roberts, B.J., Ross, S. A., & Spengler, J. L. (2008)" will precede "Roberts, B.J., Zeidler, R. L., & Madsen, R. A. (2010)" on the reference page. In-text citations appear within the research paper as (Roberts, Ross, & Spengler, 2008) and (Roberts, Zeidler, & Madsen, 2010).

Overlapping Information

• If two or more of your authors have reached the same conclusion in previous research, acknowledge both of them in the same in-text citation and separate them with a semicolon: (Ross, 2010; Roberts, 2010).