Gaya APA

Ehrlich, P, R., EHRLICH, A, H. (1970). Population Resources Environment : Issues In Human Ecology . San Fransisco: W.H. Freman and Company.

Gaya MLA

Ehrlich, Paul, R.., EHRLICH, Anne, H.. "Population Resources Environment : Issues In Human Ecology". San Fransisco: W.H. Freman and Company, 1970. Teks.