Ehrlich, P. R., & Ehrlich, A. H. (1972). Population, resources, environment: Issues in human ecology (2a. ed.). W. H. Freeman.
Chicago Style (17th ed.) ZitazioaEhrlich, Paul R., eta Anne H. Ehrlich. Population, Resources, Environment: Issues in Human Ecology. 2a. ed. San Francisco: W. H. Freeman, 1972.
MLA (9th ed.) ZitazioaEhrlich, Paul R., eta Anne H. Ehrlich. Population, Resources, Environment: Issues in Human Ecology. 2a. ed. W. H. Freeman, 1972.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.