Literature References - Cluster Analysis, Classification

[Steinhausen 1977]	D. Steinhausen, K. Langer Clusteranalyse: Einführung in Methoden und Verfahren der automatischen Klassifikation Berlin: de Gruyter, 1977
[Hastie 2009]	T. Hastie, R. Tibshirani, J. Friedman The Elements of Statistical Learning New York: Springer, 2009 An excellent textbook on multivariate data analysis which not only deals with classifiers but also with modeling.