1: http://nces.ed.gov/programs/digest/d10/tables/dt10_282.asp?referrer=list
2: http://home.honolulu.hawaii.edu/~pine/libart/ceolibarts.html
3: http://content.spencerstuart.com/sswebsite/pdf/lib/Statistical_Snapshot_of_Leading_CEOs_relB3.pdf
4: http://www.usnews.com/education/articles/2011/01/03/where-the-fortune-500-ceos-went-to-college