Keyfitz, N. (1990). World population growth and aging: Demographic trends in the late twentieth century. University of Chicago Press.
Chicago-referens (17:e uppl.)Keyfitz, Nathan. World Population Growth and Aging: Demographic Trends in the Late Twentieth Century. Chicago: University of Chicago Press, 1990.
MLA-referens (9:e uppl.)Keyfitz, Nathan. World Population Growth and Aging: Demographic Trends in the Late Twentieth Century. University of Chicago Press, 1990.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.