1. E. Denert,R. Franck,W. Streng: PLAN2D — Towards a 2-dimensional Programming Language, in Lecture Notes in Comp. Sci. 26, 202–213
2. H. Ehrig: Graph Grammars: Problems and Results in View of Computer Science Applications, Forschungsbericht 75–21 (1975), Technische Universität Berlin, Fachbereich 20
3. H. Ehrig,W. Kühnel,H.-J. Kreowski,K.D. Kiermeier: Universal Theory of Automata, Teubner, Stuttgart 1974
4. H. Ehrig, H.-J. Kreowski: Parallel Graph Grammars, in “Automata, Languages and Developement”, to be published by North-Holland 1975/76
5. H. Ehrig,M. Pfender, H.-J. Schneider: Graph Grammars, An Algebraic Approach, Proc.IEEE Conf.on Automata and Switching Theory, Iowa City 1973, 167–180