Shusaku Tsumoto Shoji Hirano Fuzziness from attribute generalization in information table. 455-461 2008 IEEE ICCI http://dx.doi.org/10.1109/COGINF.2008.4639201 conf/IEEEicci/2008 db/conf/IEEEicci/IEEEicci2008.html#TsumotoH08