4Helmuth Cremer, Pierre Pestieau. Reforming our pension system: Is it a demographic, financial or pelitieal problem ? [ J ] . European Economic Review, 44 (2000) :974 - 983.
5Anderw A Samwick. New evidence on pensions, social security, and the timing of retirement [ J ] . Journal of Public Economics, 70 (1998) : 207 - 236.
