[1] R. A. Brooks: Intelligence without representation. Artificial Intelligence 47 (1991), 139-159.

[2] R. A. Brooks: Intelligence without reason. AI Memo 1293, MIT AI Laboratory, Cambridge, Mass., 1991. Zbl 0742.68050

[3] E. Csuhaj-Varju, J. Dassow: On cooperating distributed grammar systems. J. Inform. Proc. Cybern. EIK 26 (1990), 49-63. MR 1052690 | Zbl 0693.68041

[4] E. Csuhaj-Varju J. Dassow J. Kelemen, Gh. Paun: Grammar Systems. Gordon and Breach, London 1994. MR 1475215

[5] J. Dassow: Cooperating distributed grammar systems with hypothesis languages. J. Exp. Theor. Artif. Intell. 3 (1991), 11-16.

[6] J. Dassow J. Kelemen, Gh. Paun: On parallelism in colonies. Cybernetics and Systems 24 (1993), 37-49. MR 1202093

[7] J. Dassow, Gh. Paun: Regulated Rewriting in Formal Language Theory. Springer-Verlag, Berlin - Heidelberg 1989. MR 1067543

[8] J. Gruska: Some classifications of context-free languages. Inform. and Control 14 (1969), 152-179. MR 0253836 | Zbl 0174.28901

[9] J. Gruska: Descriptional complexity of context-free languages. Proc. MFCS Symp., High Tatras, 1973, 71- 84. MR 0405938

[10] J. Kelemen: Syntactical models of distributed cooperative systems. J. Exp. Theor. Artif. Intell. 3 (1991), 1-10.

[11] J. Kelemen, A. Kelemenová: A subsumption architecture for generative symbol systems. Cybernetics and Systems Research '92, Proc. 11th European Meeting Cybern. Syst. Res. (R. Trappl, ed.), World Scientific, Singapore, 1992, pp. 1529-1536.

[12] J. Kelemen, A. Kelemenová: A grammar-theoretic treatment of multiagent systems. Cybernetics and Systems 25 (1992), 621-633.

[13] A. Kelemenová, E. Csuhaj-Varju: Languages of colonies. 2nd Intern. Coll. Words, Language, Combinatorics, Kyoto 1992.

[14] H.C.M. Kleijn, G. Rozenberg: A study in parallel rewriting systems. Inform. and Control 44 (1980), 134-163. MR 0567007 | Zbl 0436.68051

[15] V. Mitrana: Pairs grammar systems - transducers. Ann. Univ. Buc. Series Matem.-Inform. 39 (1990), 73-81. MR 1243058

[16] A. Salomaa: Formal Languages. Academic Press, New York-London 1973. MR 0438755 | Zbl 0262.68025