1. Physical activity and public health in older adults;Nelson;Recommendation from the American College of Sports Medicine and the American Heart Association,2007
2. Centers for Disease Control and Prevention. http://www.cdc.gov/nccdphp/dnpa/physical/pdf/lifestyles.pdf
3. Ageing and physical activity;Paterson;Evidence to develop exercise recommendations for older adults,2007
4. Prevalence of regular physical activity among adults-United States, 2001 and 2005;MMWR Morb Mortal Wkly Rep,2007