d SJ4-2 st0060. Production function estimation in Stata using ... d Production function estimation in Stata using inputs to control d for unobservables d by Amil Petrin d University of Chicago d NBER d d Brian P. Poi d StataCorp d d James Levinsohn d University of Michigan d NBER d Support: bpoi@@stata.com d After installation, type help ^levpet^ f st0060/levpet.ado f st0060/levpet.hlp f st0060/levpet.dlg f st0060/levpet_p.ado f st0060/lp_bs_ss.ado f st0060/nllp_bs_gmm.ado f st0060/lp_gmm.ado f st0060/lp_gmm_grid.ado f st0060/lp_srch.ado