1. Danish Labour Market Commission. Velfæd kræver arbejde Welfare request work. Copenhagen: Labour Market Commission; 2009. In Danish.
2. European Commission. Demography Report. Directorate-General for Employment, Social Affairs and Inclusion. Luxembourg: Eurostat, the Statistical Office of the European Union; 2010.
3. OECD Social Indicator. Old age support rate. 2011. http://www.oecd-ilibrary.org/social-issues-migration-health/society-at-a-glance-2011/old-age-supportrate_soc_glance-2011-10-en .
4. SOU Åtgärder för ett längre arbetsliv. Measures for an extended working life. Report 2013:25, Luxembourg: Government Offices of Sweden; 2013. (In Swedish).
5. UNFPA & HelpAge. International Ageing in the Twenty-First Century: A Celebration and A Challenge. New York: United Nations Population Fund (UNFPA) & London, HelpAge International; 2012.