1. Christensen K, Doblhammer G, Rau R, Vaupel JW. Ageing populations: the challenges ahead. Lancet. 2009;374(9696):1196–208.
2. Doyle Y, McKee M, Rechel B, Grundy E. Meeting the challenge of population ageing. BMJ. 2009;339:b3926.
3. Organisation for Economic Co-operation and Development (OECD). Sickness, disability and work: breaking the barriers. A synthesis of findings across OECD countries. Paris: OECD; 2010.
4. Niemelä H, Salminen K. Social security in Finland. Helsinki: Social Insurance Institution, Finnish Centre for Pensions, Finnish Pension Alliance and Ministry of Social Affairs and Health; 2006.
5. Pensioners and Insured in Finland 2012. Official Statistics of Finland, Social Protection. Helsinki: Finnish Centre for Pensions and Keva; 2013.