"Small sample properties of ML, COLS and DEA estimators of frontier models in the presence of heteroscedasticity" by A.N. Bojanic, S.B. Caudill and J.M. Ford, European Journal of Operational Research 108, 1998, 140-148: A comment. - Rajiv D. Banker; H. S. Chang; William W. Cooper (Eur. J. Oper. Res., 2002)