@book{28380,
	author = {Heckman, James J. and Social Science Research Council (U.S.)},
	title = {Longitudinal analysis of labor market data /},
	publisher = {Cambridge University Press,},
	year = {1985.},
	address = {Cambridge [Cambridgeshire] ;},
	note = {"Sponsored by the Social Science Research Council"--Verso t.p.},
	url = {http://www.loc.gov/catdir/description/cam031/84023253.html}
}