1. Bongaarts, J. (2006). How long will we live? Population and Development Review, 32(4), 605–628.
2. Caselli, G. (1991). Health transition and cause-SPECIFIC mortality. In R. Schofield, D. Reher, & A. Bideau (Eds.), The decline of mortality in europe. Oxford: Clarendon Press.
3. Christensen, K., Doblhammer, G., & Vaupel, J. (2009). Ageing populations: the challenges ahead. Lancet, 374(9696), 1196–1208.
4. Department for Work and Pensions. (2011). Number of future centenarians by age group. London: Department for Work and Pensions.
5. Dublin, L. I. (1928). Health and wealth. New York: Harper.