Scientific American, December 2005 Bruce P Kennedy, Ichiro Kawachi, Deborah Prothrow-Stith (1996) Income distribution and mortality: cross sectional ecological study of the Robin Hood index in the United States, BMJ 312:1004–07 External links Free Inequality Calculator: Online and downloadable scripts (Python and Lua) for Atkinson, Gini, and Hoover inequalities Income inequality metrics Welfare economics