Cita APA (7a ed.)

Ridley, M. (1996). The origins of virtue (1st. ed.). Penguin Books.

Cita Chicago Style (17a ed.)

Ridley, Matt. The Origins of Virtue. 1st. ed. Harmondsworth, Middlesex: Penguin Books, 1996.

Cita MLA (9a ed.)

Ridley, Matt. The Origins of Virtue. 1st. ed. Penguin Books, 1996.