Duran, B. S. and Odell, P. L. (1974), Cluster Analysis, New York: Springer-Verlag.

Everitt, B. S. (1980), Cluster Analysis, Second Edition, London: Heineman Educational Books.

Fisher, R. A. (1936), “The Use of Multiple Measurements in Taxonomic Problems,” Annals of Eugenics, 7, 179–188.

Hand, D. J., Daly, F., Lunn, A. D., McConway, K. J., and Ostrowski, E. (1994), A Handbook of Small Data Sets, London: Chapman & Hall.

Hartigan, J. A. (1975), Clustering Algorithms, New York: John Wiley & Sons.

Johnson, S. C. (1967), “Hierarchical Clustering Schemes,” Psychometrika, 32, 241–254.

Knuth, D. E. (1973), The Art of Computer Programming, Volume 1, Fundamental Algorithms, Reading, MA: Addison-Wesley.