Zaitsev D.A. Invariants of Timed Petri Nets, Cybernetics and Systems Analysis, Volume 40, Number 2 (2004), 226-237.
Zaitsev D.A., Sleptsov A.I. State equations and equivalent transformations for timed Petri nets, Cybernetics and Systems Analysis, Volume 33, Number 5 (1997), 659-672.
Solving operative management tasks of a discrete manufacture via Petri net models. PhD thesis. (Thesis / Abstract) // Kiev, the Academy of sciences of Ukraine, Institute of Cybernetics name of V.M.Glushkov, 1991. In Russ.