Sanghyuk Lee Sangjin Kim Nam-Young Jang Design of Fuzzy Entropy for Non Convex Membership Function. 55-60 2008 ICIC (3) http://dx.doi.org/10.1007/978-3-540-85930-7_8 conf/icic/2008-3 db/conf/icic/icic2008-3.html#LeeKJ08