1. Worker remittances and inequality in rural Egypt;Adams;Econ. Dev. Cultural Change,1989
2. Abnormal selection bias;Goldberger,1983
3. Sample selection bias as a specification error;Heckman;Econometrica,1979
4. The comon structure of statistical models of truncation, sample selection and limited depedndent variables and a simple estimator for such models;Heckman;Ann. Econ. Soc. Measurements,1976