Cita APA (7a ed.)

Singer, P. (1981). The expanding circle: Ethics and sociobiology. Farrar, Straus Giroux.

Cita Chicago Style (17a ed.)

Singer, Peter. The Expanding Circle: Ethics and Sociobiology. New York, NY: Farrar, Straus Giroux, 1981.

Cita MLA (8a ed.)

Singer, Peter. The Expanding Circle: Ethics and Sociobiology. Farrar, Straus Giroux, 1981.