Trimmed Lad and Least Squares Estimation of Truncated and Censored Regression Models with Fixed Effects Bo E. Honore Econometrica, Vol. 60, No. 3. (May, 1992), pp. 533-565. Stable URL: http://links.jstor.org/sici?sici=0012-9682%28199205%2960%3A3%3C533%3ATLALSE%3E2.0.CO%3B2-2