作者:SOLOW, RM; JOHNSON, DG; LAMPMAN, RJ; SAFFRON, B
作者单位:Massachusetts Institute of Technology (MIT); University of Chicago; University of Wisconsin System; University of Wisconsin Madison; Swarthmore College
作者:CRANDALL, RW; KEELER, TE; LAVE, LB
作者单位:Brookings Institution; University of California System; University of California Berkeley; Carnegie Mellon University