1. Climbing Staff. Forever: 80-years-old and still climbing. Climbing Magazine. https://www.climbing.com/videos/forever-80-years-old-and-still-climbing/. Published 2017. Accessed February 5, 2019.
2. Progress on understanding ageism;Levy;J Soc Issues.,2016
3. Tippett R. Population Aging and Growing Dependency | StatChat. University of Virginia. http://statchatva.org/2012/11/20/population-aging-and-growing-dependency/. Published 2012. Accessed February 12, 2019.
4. U.S. Census Bureau. Older Americans Month: May 2017. https://www.census.gov/newsroom/facts-for-features/2017/cb17-ff08.html. Published 2017. Accessed February 5, 2019.
5. U.S. Census Bureau. Nation’s Older Population to Nearly Double. https://www.census.gov/newsroom/press-releases/2014/cb14-84.html. Published 2014. Accessed February 5, 2019.