I am looking for a Stata (or R/Matlab if there's no Stata) implementation of the model described by Greene (1994) (http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1293115).
It is essentially a Heckit for ZINB instead of OLS.
Would anyone know if such an implementation exists? Also, a critical formula in this model (3.6, p18) is somehow missing from the Working Paper. If anyone knows of another version that has it, that would be greatly, appreciated.