Malthus (1926), hlm. 13, "Assuming then, my postulata asgranted, I say, that the power of population is indefinitely greater than the power in the earth to produce subsistence for man." Malthus, Thomas Robert (1926). An Essay on the Principle of Population (dalam bahasa Inggris). London: Macmillan & co.Ltd.Parameter |url-status= yang tidak diketahui akan diabaikan (bantuan)