Lefton, L. A. (1997). Psychology (6th ed.). Kentucky State University.
Cita Chicago (17th ed.)Lefton, Lester A. Psychology. 6th ed. Kentucky: Kentucky State University, 1997.
Cita MLA (9th ed.)Lefton, Lester A. Psychology. 6th ed. Kentucky State University, 1997.
Atenció: Aquestes cites poden no estar 100% correctes.