1. United States Census Bureau. Age and Sex. (online). Available at: http://www.census.gov/topics/population/age-and-sex.html. Accessed December 8, 2014
2. United Nations, Department of Economic and Social Affairs, Population Division. World Population Ageing 2013. ST/ESA/SER.A/348. (online). Available at: http://www.un.org/en/development/desa/population/publications/pdf/ageing/WorldPopulationAgeing2013.pdf. Accessed December 8, 2014
3. A study of sexuality and health among older adults in the United States;Lindau;N Engl J Med,2007
4. Sexuality and intimacy in older adults;Rheaume;Geriatr Nurs,2008
5. Sexual health and function in later life: a population-based study of 606 older adults with a partner;Wang;Am J Geriatr Psychiatry,2015