1. Gh.Paun, L.Santean: Parallel communicating grammar systems: the regular case. Ann.Univ.Buc.Ser.Mat.-Inform. 37 vol. 2(1989), pp. 55–63.
2. J.E.Hopcroft, J.D.Ullman: Formal Languages and Their Relation to Automata. Addison-Wesley Publishing Company, Reading, Massachusetts, 1969.
3. G.T.Herman, G.Rozenberg: Developmental Systems and Languages, North-Holland, Amsterdam, 1975.
4. J.Hromković, J.Kari, L.Kari: Some hierarchies for the communication complexity measures of cooperating grammar systems. Theoretical Computer Science, to appear (extended abstract in: Proc. of the MFCS'93 Lecture Notes in Comp. Science 711, pp. 495–505).
5. M.Lukáč: About two communication structures of PCGS. Master Thesis(1992), Dept.of Comp.Sci., Faculty of Mathematics and Physics, Comenius University, Bratislava (in Slovak).