1. Robust estimates, residuals, and outlier detection with multiresponse data;Gnanadesikan;Biometrics,1972
2. The influence curve and its role in robust estimation;Hampel;J. Amer. Statist. Assoc.,1974
3. Hampel, F. R. (1975). Beyond location parameters: Robust concepts and methods. 40th Session International Statistical Institute, Warsaw.
4. Robust estimation of a location parameter;Huber;Ann. Math. Statist.,1964