作者：ALTONJI, JG; HAM, JC
作者单位：Pennsylvania Commonwealth System of Higher Education (PCSHE); University of Pittsburgh; National Bureau of Economic Research; Northwestern University
作者：EARLE, JS; PENCAVEL, J
作者单位：Brookings Institution; National Bureau of Economic Research
作者：FREEMAN, RB; KLEINER, MM
作者单位：National Bureau of Economic Research; University of Minnesota System; University of Minnesota Twin Cities
