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.
Atenció: Aquestes cites poden no estar 100% correctes.