1. There are arguments that unfunded and funded systems are both claims on future output of an economy and therefore, as ageing affects this future output, are equally affected. However, this means assuming a closed economy, but through international investments, future pensioners can establish claims to the output of younger economies. See, Barr, N. and Diamond, P. (2006) The economics of pensions. Oxford Review of Economic Policy 22 (1): 15–39.
2. See European Union. (2006) Adequate and Sustainable Pensions. Synthesis Report 2006. http://ec.europa.eu/employment_social/social_protection/docs/2006/rapport_pensions_final_en.pdf .
3. See United Nations World Population Database: The 2006 Revision Population Database. http://esa.un.org/unpp/ .
4. SeeWorld Bank. (1994) Averting the Old-Age Crisis. New York: Oxford University Press.
5. For an overview of the literature, see Davis, P. and Hu, Y.-W. (2006) Funding, saving, and economic growth. In: G. Clark, A. Munnell and M. Orszag (eds.) The Oxford Handbook of Pensions and Retirement Income. Oxford: Oxford University Press, pp. 201–218.