1. Braveman , P. S. Egerter 2008 Overcoming obstacles to health: Report from the Robert Wood Johnson Foundation to the Commission to Build a Healthier America
2. U.S. Census Bureau 2008 Current Population Survey, Annual Social and Economic Supplements. Retrieved on December 1, 2008 from Inequality.org at http://www.census.gov/hhes/www/income/histinc/f03ar.html
3. http://www.healthypeople.gov/Data/midcourse/html/execsummary/introduction.htm