EHRLICH, P. R., EHRLICH, A. H., & HOLDREN, J. P. (1973). Human ecology: Problems and solutions. W.H. Freeman.
Lua i Stíl Chicago (17ú heag.)EHRLICH, Paul R., Anne H. EHRLICH, agus John P. HOLDREN. Human Ecology: Problems and Solutions. San Francisco: W.H. Freeman, 1973.
Lua MLA (9ú heag.)EHRLICH, Paul R., et al. Human Ecology: Problems and Solutions. W.H. Freeman, 1973.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.