Referencias
U.S. Department of Health and Human Services. 2008 Physical Activity Guidelines for Americans. Accessed February 22, 2009.
U.S. Preventive Services Task Force. Guide to clinical preventive services 2008. Rockville, MD. 2008. AHRQ publications 08-05122.
Woolf SH. Principles of preventive health care. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 12.