Cita APA (7th ed.)

Singer, P. (1990). Animal liberation (2nd ed.). Avon Books.

Cita Chicago (17th ed.)

Singer, Peter. Animal Liberation. 2nd ed. New York, N.Y: Avon Books, 1990.

Cita MLA (9th ed.)

Singer, Peter. Animal Liberation. 2nd ed. Avon Books, 1990.