1. Cohn D, Taylor P. Baby boomers approach 65—glumly. Pew Research Social & Demographic Trends. 2010. http://www.pewsocialtrends.org/2010/12/20/baby-boomers-approach-65-glumly/ . Accessed on 14 Aug 2018.
2. Wan H, Sengupta M, Velkoff VA, DeBarrow KA. 65+ in the United States: 2005 current population reports. 2005.
3. Colby SL, Ortman JM. Projections of the size and composition of the US population: 2014 to 2060: population estimates and projections. 2017.
4. World Health Organization. World report on ageing and health. World Health Organization. 2015. http://www.who.int/ageing/events/world-report-2015-launch/en/ . Accessed on 14 Aug 2018.
5. McPhee JS, French DP, Jackson D, Nazroo J, Pendleton N, Degens H. Physical activity in older age: perspectives for healthy ageing and frailty. Biogerontology. 2016:1–14.