BVU                     Bonus vetus OLS, BVU
BVW                     Bonus vetus OLS, BVW
DDM                     Double Demeaning, DDM
EK_Tobit                Eaton and Kortum (2001) Tobit model, EK_Tobit
ET_Tobit                Eaton and Tamura (1994) threshold Tobit model,
                        ET_Tobit
Fixed_Effects           Fixed_Effects
GPML                    Gamma Pseudo Maximum Likelihood, GPML
Gravity_no_zeros        Gravity dataset without zero trade flows
Gravity_zeros           Gravity dataset with zero trade flows
NBPML                   Negative Binomial Pseudo Maximum Likelihood,
                        NBPML
NLS                     Nonlinear Least Squares, NLS
OLS                     OLS
PPML                    Poisson Pseudo Maximum Likelihood, PPML
SILS                    Structural Iterated Least Squares, SILS
Tetrads                 Tetrads
Tobit                   Left-censored Tobit model with known threshold
