Cita APA (7a ed.)

Trahan, M., & Gray, P. (2007). Focus on psychology: A guide to mastering Peter Gray's Psychology (5th.ed.). Worth Publishers..

Cita Chicago Style (17a ed.)

Trahan, Mary, y Peter Gray. Focus on Psychology: A Guide to Mastering Peter Gray's Psychology. 5th.ed. New York: Worth Publishers., 2007.

Cita MLA (9a ed.)

Trahan, Mary, y Peter Gray. Focus on Psychology: A Guide to Mastering Peter Gray's Psychology. 5th.ed. Worth Publishers., 2007.