“…These models are highly parametric and rely on strong distributional assumptions for identification. Models of this sort have been considered by, among others, Lau and Yotopoulos (1971), Toda (1976), Atkinson and Halvorsen (1980), Lovell and Sickles (1983), Sickles et al (1986), Kumbhakar (1987), Good et al (1991), Atkinson and Cornwell (1994), and Good et al (1997). For an excellent review of this class of models as well as the methods we address herein see Greene (1997) and Lovell and Kumbhakar (2000).…”