1. [AK]: T. Araki, T. Kasami; DECIDABLE PROBLEMS ON THE STRONG CONNECTIVITY OF PETRINET REACHABILITY SETS, Theoretical Computer Science, Vol. 4, pp.99–119, 1977.
2. [C]: L. A. Castellano; BETA PROCESSES OF C/E-SYSTEMS; 6th European Workshop on Application and Theory of Petri Nets, Espoo, Finland, 1985.
3. [B]: W. Brauer (ed.); NET THEORY AND APPLICATIONS, Lecture Notes in Computer Science Vol. 84, Springer Verlag, 1980.
4. [G]: U. Goltz; SYNCHRONIEABSTÄNDE IN BEDINGUNGS/EREIGNIS-SYSTEMEN, Diplomarbeit RWTH Aachen, 1982.
5. [GLT]: H.J. Genrich, K. Lautenbach, P.S. Thiagarajan; ELEMENTS OF GENERAL NET THEORY, included in [B].