Ridker, R. G. (1972). Population resources, and the environment. Government Printing Office.
Citazione stile Chigago Style (17a edizione)Ridker, Ronald Gene. Population Resources, and the Environment. Washington, D.C: Government Printing Office, 1972.
Citatione MLA (9a ed.)Ridker, Ronald Gene. Population Resources, and the Environment. Government Printing Office, 1972.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.