Jonathan Lee Kevin F. R. Liu Yao-Chiang Wang Weiling Chiang Possibilistic Petri nets as a basis for agent service description language. 105-126 2004 144 Fuzzy Sets and Systems 1 http://dx.doi.org/10.1016/j.fss.2003.10.016 db/journals/fss/fss144.html#LeeLWC04