Toshihiko Matsuka Yasuaki Sakamoto A Cognitive Model of Concept Learning with a Flexible Internal Representation System. 1135-1143 2007 conf/isnn/2007-1 ISNN (1) https://doi.org/10.1007/978-3-540-72383-7_133 db/conf/isnn/isnn2007-1.html#MatsukaS07