@techreport{Heckman2003,
author = {Heckman, J.J. and Lochner, L.J. and Todd, P.E.},
title= {Fifty years of Mincer earnings regressions},
year = {2003},
doi = {10.3386/w9732},
publisher = {National Bureau of Economic Research},
address = {Cambridge},
number = {NBER working paper no. 9732},
}