1. U.S. Census Bureau http://factfinder.census.gov/servlet/ADPTable?_bm=y&-geo_id=01000US&-qr_name=ACS_2007_1YR_G00_DP5&-ds_name=&-_lang=en&-redoLog=false&-format
2. U.S. Department of Health and Human Services http://assets.aarp.org/rgcenter/general/profile_2005.pdf
3. The prevalence of elder abuse;Pillemer;A random sample survey,1988