Chengjia Li Yifan Cai Fuling Ding Product Supervisor for Fuzzy Discrete Event Systems. 391-395 2008 FSKD (1) http://dx.doi.org/10.1109/FSKD.2008.237 conf/fskd/2008-1 db/conf/fskd/fskd2008-1.html#LiCD08