I encountered a source text that had two authors, Paul Ehrlich and Anne H. Ehrlich.

And I want to use the proper APA method to cite them.

Should I use this one:

As Ehrlich and Ehrlich underlined, ... (2015)

or this one:

As P. Ehrlich and A. Ehrlich underlined, ... (2015)

  • I mean how to cite the source of two authors with same surnames?
    – Shadovx
    May 5, 2019 at 19:17
  • Please include your research in the question.
    – shoover
    May 5, 2019 at 19:29
  • Are the rest of your citations given as last name only? Then use "Ehrlich and Ehrlich".
    – GEdgar
    May 5, 2019 at 19:29
  • Please do some homework. Check how journals in your field deal with this — what you are asking is house style. But whatever journal or publication, wanna is a gonna.
    – David
    May 5, 2019 at 19:30
  • I learned the same as @David . Say "want to" not "wanna". But, in fact, nowadays "wanna" is found in all dictionaries, so David and I are just out of date.
    – GEdgar
    May 5, 2019 at 19:32

2 Answers 2


In your case, you have a single book authored by two people with the same surname but different initials.

Your in-text citation would look like this:

As P. Ehrlich and Ehrlich underlined,  . . . (2015)

And your reference list entry would look like this:

Ehrlich, P., & Ehrlich, A. . . .

The explanation for this follows.

The Publication Manual of the American Psychological Association (6th ed.), 6.14, says this about reference lists:

If a reference list includes publications by two or more primary authors with the same surname, include the first author's initials in all text citations, even if the year of the publication differs. Initials help the reader to avoid confusion within the text and to locate the entry in the list of references.


      Light, I. (2006). Deflecting immigration: Networks, Markets, and regulation in Los Angeles. New York, NY: Russel Sage Foundation

      Light, M. A., & Light I. H. (2008). The geographic expansion of Mexican immigration in the United States and its implications for local law enforcement. Law Enforcement Executive Forum Journal, 8, 73—82.

      Text Cites:

      Among studies, we review M. A. Light and Light (2008) and I. Light (2006).

Note that the in-text citation for the coauthored book uses the first author's initials and surname, but only the second author's surname. This matches your own example.

Here is some additional information.

APA, 6.25:

Arrange works by different authors with the same surname alphabetically by first initial:

      Mathur, A. L., & Wallston, J. (1999).
      Mathur, S. E., & Ahlers, R. J. (1998).

APA, 6.27:

If the reference list includes different authors with the same surname and the first initial, the authors' full first names may be given in brackets:

      Janet, P. [Paul]. (1876). La notion de la personnalite [The notion of personality]. Revue Scientifique, 10, 574–575.
      Janet, P. [Pierre]. (1906). The pathogenesis of some impulsions. Journal of Abnormal Psychology, 1, 1–17.

      In text:
      (Paul Janet, 1876)
      (Pierre Janet, 1906)


With two authors with the same name in-text citation P. Ehrlich (2015) and A. Ehrlich (2015) underlined, ... or (Ehrlich, P., 2015; Ehrlich, A., 2015)

  • 1
    Hi jangjang, and welcome to Writing SE and Stack Exchange. We generally prefer answers that go into some depth, provide citations for claims made, and that add something not previously said. Your answer is different from the existing answer on the question, but provides no substantiation of the different claim you make. Can you Edit your answer to tell us more about why what you propose is the correct answer?
    – user
    May 9, 2019 at 11:11

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