1. Centers for Medicare and Medicaid Services, Office of the Actuary, National Health Statistics Group: 2007 National Health Care Expenditures Data (March 2009)
2. http://apps.nccd.cdc.gov/brfss/display.asp?yr=2008&cat=HS&qkey=1100&state=US
3. http://www.cdc.gov/nccdphp/
4. http://www.apa.org/releases/stressproblem.html
5. The American Stress Institute. Stress, Definition of Stress, Stressor, What is Stress?, Eustress?
http://www.stress.org