R. Kruse, C. Borgelt, and D. Nauck. Intelligent Systems and Soft Computing, volume 1804 of Lecture Notes in Computer Science, page 95-109. Springer, (2000)
C. Borgelt, J. Gebhardt, and R. Kruse. Computational Intelligence in Data Mining, volume 408 of International Centre for Mechanical Sciences (CISM) Book Series, Springer, (2000)