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by Durlauf, Steven; Hansen, Lars Peter; Heckman, James J.; et al.
by Heckman, James J.; Humphries, John Eric; Kautz, Tim
by Heckman, James J.
by edited by James J. Heckman and Carmen Pages
by Morgan, Matthew J.; Heckman, James J.
by Heckman; James J.
by Edited by James J. Heckman , Burton S. Singer