Cita APA (7th ed.)

Schroeder, D. A., & Penner, L. A. (1995). The psychology of helping and altruism: Problems and puzzles. McGraw-Hill.

Cita Chicago (17th ed.)

Schroeder, David A., i Louis A. Penner. The Psychology of Helping and Altruism: Problems and Puzzles. New York: McGraw-Hill, 1995.

Cita MLA (9th ed.)

Schroeder, David A., i Louis A. Penner. The Psychology of Helping and Altruism: Problems and Puzzles. McGraw-Hill, 1995.