Day, W. H. and Edelsbrunner, H. Efficient algorithms for agglomerative hierarchical clustering methods. Journal of Classification, 1. 7-24. 1984.
Johnson, S. C. Hierarchical clustering schemes. Psychometrika, 32. 241-254. 1967.
Latané, B. Dynamic social impact: The creation of culture by communication. Journal of Communication, 46. 13-25. 1996.
The R Core Team. R: A language and environment for statistical computing. R Foundation for Statistical Computing. 2013.
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