Valentino Dardanoni, University of Palermo, Gary S. Fields, Cornell University, John E. Roemer, Yale University, Maria Laura Sánchez Puerta, The World Bank (2006), “How Demanding Should Equality of Opportunity Be, and How Much Have We Achieved?”, Cornell University -- Digital Commons ILR, http://digitalcommons.ilr.cornell.edu/articles/270/2012年7月24日閲覧, "(from the abstract:) ...Agreement is widespread that equality of opportunity holds in a society if the chances that individuals have to succeed depend only on their own efforts and not on extraneous circumstances..."
