New Directions in Rough Sets, Data Mining, and Granular-Soft Computing 7th International Workshop, RSFDGrC'99, Yamaguchi, Japan, November 9-11, 1999 Proceedings - Zhong, Ning; Zhong, Ning; Ohsuga, Setsuo; Ohsuga, Setsuo (Springer Berlin Heidelberg : Imprint: Springer, 1999)