Ehrlich, P. R., & Ehrlich, A. H. (1970). Population resources environment: Issues in human ecology. W.H. Freeman and Company.
Čikaški stil citiranja (17. izdanje)Ehrlich, Paul R., i Anne H. Ehrlich. Population Resources Environment: Issues in Human Ecology. San Francisco, CA: W.H. Freeman and Company, 1970.
MLA način citiranja (9. izdanje)Ehrlich, Paul R., i Anne H. Ehrlich. Population Resources Environment: Issues in Human Ecology. W.H. Freeman and Company, 1970.
Upozorenje: Ovi citati možda nisu uvijek 100% točni.