APA (7th ed.) Citation

Trahan, M., & Gray, P. (1991). Focus on psychology: A guide to mastering Peter Gray's psychology. Worth.

Chicago Style (17th ed.) Citation

Trahan, Mary, and Peter Gray. Focus on Psychology: A Guide to Mastering Peter Gray's Psychology. New York: Worth, 1991.

MLA (9th ed.) Citation

Trahan, Mary, and Peter Gray. Focus on Psychology: A Guide to Mastering Peter Gray's Psychology. Worth, 1991.