http://content.knightfrank.com/research/83/documents/en/wealth-report-2016-3579.pdf

http://www.brookings.edu/blogs/social-mobility-memos/posts/2016/03/25-make-elites-compete-why-one-percent-earn-so-much-rothwell?utm_campaign=Brookings+Brief&utm_source=hs_email&utm_medium=email&utm_c ontent=27718973&_hsenc=p2ANqtz-8K0JGt-N7jNzQNckTZZLW23GUJZB9b1_gH_6qFEZvEDq9B5yuA9cHs7ghVMHcxDh2gnyMfIz UmZVCusulhgDVP4b4qvfLqKfGCAirYTDEtFrF5Rk0&_hsmi=27718973

http://www.oecd-ilibrary.org/docserver/download/0115391e.pdf?expires=1459174835&id=id&accname=guest&checksum=ED1AECD35EE597AE051 8DC7BB69A45AC