APA
Heckman J., National Bureau Of Economic Research, . (1994). Econometric Mixture Models And More General Models For Unobservables In Duration Analysis. Cambridge, MA: NBER.
Chicago
Heckman JJ, National Bureau Of Economic Research, . 1994. Econometric Mixture Models And More General Models For Unobservables In Duration Analysis. Cambridge, MA: NBER.
Harvard
Heckman J., National Bureau Of Economic Research, . (1994). Econometric Mixture Models And More General Models For Unobservables In Duration Analysis. Cambridge, MA: NBER.
MLA
Heckman JJ, National Bureau Of Economic Research, . Econometric Mixture Models And More General Models For Unobservables In Duration Analysis. Cambridge, MA: NBER. 1994.