Cita APA (7th ed.)

Ehrlich, A. H., & Ehrlic, P. R. (1987). Earth. Methun.

Cita Chicago (17th ed.)

Ehrlich, Anne H., i Paul R. Ehrlic. Earth. London: Methun, 1987.

Cita MLA (9th ed.)

Ehrlich, Anne H., i Paul R. Ehrlic. Earth. Methun, 1987.