Dhillon, I. S.; Modha, D. S. & Spangler, W. S. (2002), 'Class visualization of high-dimensional data with applications', Computational Statistics & Data Analysis 41 (1), 59-90.

Bezdek, J. C.; Li, W. Q.; Attikiouzel, Y. & Windham, M. (1997), 'A geometric approach to cluster validity for normal mixtures', Soft Computing - A Fusion of Foundations, Methodologies and Applications 1 (4), 166--179.

Kaufman, L. & Rousseeuw, P. J. (1990), Finding Groups in Data: An Introduction to Cluster Analysis , John Wiley .

Rand, W. (1971), 'Objective criteria for the evaluation of clustering methods', Journal of the American Statistical Association 66 (336), 846-850.