Cita APA (7th ed.)

Ehrlich, A. H., & Ehrlich, P. R. (1987). Earth. Thames Methuen.

Cita Chicago (17th ed.)

Ehrlich, Anne H., i Paul R. Ehrlich. Earth. London: Thames Methuen, 1987.

Cita MLA (9th ed.)

Ehrlich, Anne H., i Paul R. Ehrlich. Earth. Thames Methuen, 1987.