18578 Janos Abonyi/Balasz Feil/Ajith Abraham: Computational intelligence
in data mining. Informatica 29 (2005), 3-12.

Hans Hermann Bock (ed.): Klassifikation und Erkenntnis III. 1979.

Hans Hermann Bock: Clusteranalyse mit unscharfen Partitionen.
In Bock 1979, 137-163.

T. Gu/B. Dubuisson: Similarity of classes and fuzzy clustering.
Fuzzy sets and systems 34 (1990), 213-221.

M. Gupta/T. Yamakawa (ed.): Fuzzy computing theory, hardware, and applications.
1988.

M. Ismail: Soft clustering. Algorithms and validity of solutions.
In Gupta/Yamakawa (1988), 445-471.