Cita APA (7a ed.)

Darwin, C. R., & Ekman, P. (1998). The expression of the emotions in man and animals (3rd ed.). HarperCollins.

Cita Chicago Style (17a ed.)

Darwin, Charles Robert, y Paul Ekman. The Expression of the Emotions in Man and Animals. 3rd ed. London: HarperCollins, 1998.

Cita MLA (9a ed.)

Darwin, Charles Robert, y Paul Ekman. The Expression of the Emotions in Man and Animals. 3rd ed. HarperCollins, 1998.