Ehrlich, Paul R. Ehrlich & Anne H. (1990). The population explosion. London: Hutchinson. стр. 39—40. ISBN978-0091745516. Приступљено 20. 7. 2014. „When is an area overpopulated? When its population cannot be maintained without rapidly depleting nonrenewable resources [39] (or converting renewable resources into nonrenewable ones) and without decreasing the capacity of the environment to support the population. In short, if the long-term carrying capacity of an area is clearly being degraded by its current human occupants, that area is overpopulated.”
