1. OBJSA nets: a class of high-level nets having objects as domains;Battiston,1988
2. Morphisms and minimal models for OBJSA nets;Battiston,1991
3. Modular functional modelling of Petri nets with individual tokens;Broy,1992
4. Hierarchical high level Petri nets for complex system analysis;Buchholz,1994
5. Coloured Petri nets extended with channels for synchronous communication;Christinsen,1994