Hartigan, J.A. (1975). Clustering algorithms. New York: Wiley.
4.
Sneath, P.H.A. (1980). The probability that distinct clusters will be unrecognized in low dimensional ordinations. Classification Society Bulletin, 4, 22-43.
5.
Sneath, P.H.A., & Sokal, R.R. (1973). Principles of numerical taxonomy. San Francisco: Freeman.
6.
Spath, H. (1980). Cluster analysis algorithms. New York: Wiley.