1. Pew Research Internet Project2014012014-03-02Internet User Demographicshttp://www.pewinternet.org/data-trend/internet-use/latest-stats/6Nm3n9Gyj
2. Department of Health and Human Services, Administration on Aging20132013-07-11Aging Statisticshttp://www.aoa.gov/Aging_Statistics/6I1ojlqWD
3. National Center for Chronic Disease Prevention and Health PromotionState of Aging and Health in America20132014-08-16Atlanta, GACenters for Disease Control and Preventionhttp://www.cdc.gov/features/agingandhealth/state_of_aging_and_health_in_america_2013.pdf6RrHpBlDS
4. 2008 Physical Activity Guidelines for Americans: fact sheet for health professionals on physical activity guidelines for Americans2009062010-12-21Atlanta, GACenters for Disease Control and Prevention, Division of Nutrition, Physical Activity, and Obesityhttp://www.cdc.gov/nccdphp/dnpa/physical/pdf/PA_Fact_Sheet_OlderAdults.pdf5v8F3OlEz
5. Physical Activity in the United States Measured by Accelerometer