American Medical Directors Association. (2004). Clinical corner: Pain management. Retrieved June 7, 2004.
American Society for Pain Management Nursing
National Guideline Clearinghouse/Agency for Healthcare Research and Quality. (2002, Modified June 7, 2004). The management of persistent pain in older persons. Retrieved June 7, 2004.
United States Department of Health and Human Services: Aging
Last updated - January 2005