Cita APA (7th ed.)

Pirages, D. C., & Ehrlich, P. R. (1974). Ark II: Social response to environmental imperatives. Freeman.

Cita Chicago (17th ed.)

Pirages, Dennis C., i Paul R. Ehrlich. Ark II: Social Response to Environmental Imperatives. San Francisco: Freeman, 1974.

Cita MLA (9th ed.)

Pirages, Dennis C., i Paul R. Ehrlich. Ark II: Social Response to Environmental Imperatives. Freeman, 1974.