1. Hoffman R (2008) Socioeconomic differences in old age mortality. Rostock: Springer.
2. The added years: elderly in India and Kerala;L Gulati;Economic and Political Weekly,1999
3. Harper S (2006) Ageing societies: myths, challenges and opportunities. New York: Oxford University Press.
4. Martin LG, Preston SH, eds. (1994) Demography of Aging. Washington: National Academy Press.
5. United Nations (2007) World population ageing: 1950–2050. In Department of Economic and Social Affairs. New York: Population Division.