[1] Smith, Adam: An Inquiry into the Nature And Causes of the Wealth of Nations Book 2 – Of the Nature, Accumulation, and Employment of Stock; Published 1776. [وصلة مكسورة]نسخة محفوظة 10 يناير 2010 على موقع واي باك مشين.
Rindermann، Heiner (مارس 2008). "Relevance of education and intelligence at the national level for the economic welfare of people". Intelligence. ج. 36 ع. 2: 127–142. DOI:10.1016/j.intell.2007.02.002.
Claudia Goldin، Department of Economics Harvard University and National Bureau of Economic Research. "Human Capital"(PDF). مؤرشف من الأصل(PDF) في 2019-08-04.
Claudia Goldin، Department of Economics Harvard University and National Bureau of Economic Research. "Human Capital"(PDF). مؤرشف من الأصل(PDF) في 2019-08-04.
[1] Smith, Adam: An Inquiry into the Nature And Causes of the Wealth of Nations Book 2 – Of the Nature, Accumulation, and Employment of Stock; Published 1776. [وصلة مكسورة]نسخة محفوظة 10 يناير 2010 على موقع واي باك مشين.