References/Notes/Attributions:
Source
Weisberg, S. (1985) Applied Linear Regression. 2nd edition. Wiley, pp. 144–5.
P. J. Rousseeuw and A. M. Leroy (1987) Robust Regression and Outlier Detection. Wiley, p. 57.
References
Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Forth Edition. Springer.