Yong Yu Tong Li Qing Liu Fei Dai Na Zhao OR-transition Colored Petri Net and its Application in Modeling Software System. 15-18 2009 WKDD http://dx.doi.org/10.1109/WKDD.2009.23 conf/wkdd/2009 db/conf/wkdd/wkdd2009.html#YuLLDZ09