1. Wan H, Sengupta M, Velkoff V, DeBarros K (2005) 65+ in the United States: 2005. U.S. Census Bureau, Washington, DC
2. Hetzel L, Smith A (2001) The 65 years and over population: 2000. U.S. Census Bureau, Washington, DC
3. Myers GC (1990) Demography of aging. In: Binstock RH, George LK (eds) Handbook of aging and the social sciences. Academic, New York, pp 19–44
4. Thomlinson R (1976) Population dynamics. Causes and consequences of world demographic change. Random House, New York
5. Moore TJ (1993) Lifespan. Simon and Schuster, New York