4David R, Alia H. Discrete, continuous, and hybrid Petri nets [M]. Berlin: Springer-Verlag,2010.
5Lefebvre D, Delherm C, Leclercq E, et al, Some contri- bution with Petri nets for the modeling, analysis and con- trol of HDS[J]. Nonlinear Analysis:Hybrid Systems, 2007, 1 (4) :451-465.
6Chen S M, Ke J S, Chang J F. Knowledge representation using fuzzy Petri nets [J]. IEEE Transactions on Knowl- edge and Data Engineering, 1990,2 (3) : 311-319.