Cita APA (7a ed.)

Callahan, S., & Callahan, D. (1984). Abortion: Understanding differences. Plenum Press.

Cita Chicago Style (17a ed.)

Callahan, Sidney, y Daniel Callahan. Abortion: Understanding Differences. New York [u.a.]: Plenum Press, 1984.

Cita MLA (8a ed.)

Callahan, Sidney, y Daniel Callahan. Abortion: Understanding Differences. Plenum Press, 1984.