1. Aczel, P., An introduction to inductive definitions. In the handbook of Mathematical Logic, Ed. Barwise, J., North-Holland (1983).
2. Arbib, M.A.,and Manes,E.G., Arrows, Structures and Functors, The categorical imperative. Academic Press (1975).
3. Arbib, M.A.,and Manes,E.G., Formal semantics of programming languages. Final version forthcoming, preliminary version (1982).
4. Brauer, W.(Ed.), Net Theory and Applications, Springer-Verlag Lecture Notes in Comp. Sci., vol.84 (1980).
5. Boudol, G, Roucairol, G., and de Simone, R., Petri nets and algebraic calculi of processes. Submitted to Advances in Petri nets (1985).