Cita APA (7a ed.)

Ehrlich, P. R., Ehrlich, A. H., & Holdren, J. P. (1973). Human ecology: Problems and solutions. W.H. Freeman.

Cita Chicago Style (17a ed.)

Ehrlich, Paul R., Anne H. Ehrlich, y John P. Holdren. Human Ecology: Problems and Solutions. San Francisco: W.H. Freeman, 1973.

Cita MLA (9a ed.)

Ehrlich, Paul R., et al. Human Ecology: Problems and Solutions. W.H. Freeman, 1973.