APA (7th ed.) Citation

Ehrlich, P. R., & Ehrlich, A. H. (1972). Population resources environment issues in human ecology.

Chicago Style (17th ed.) Citation

Ehrlich, Paul R., and Anne H. Ehrlich. Population Resources Environment Issues in Human Ecology. W.H. Freeman and Company, 1972.

MLA (9th ed.) Citation

Ehrlich, Paul R., and Anne H. Ehrlich. Population Resources Environment Issues in Human Ecology. 1972.