1. Denert,E./ Ehrig,H.: Mehrdimensionale Sprachen, lecture manuscript, TU Berlin 1976.
2. Techn. Report;H. Ehrig,1975
3. Ehrig,H.: Introduction to the Algebraic Theory of Graph Grammars, Proc. International Workshop on Graph Grammars and Their Applications to Computer Science and Biology, Bad Honnef 1978, this volume.
4. Nagl,M.: A Tutorial and Bibliographical Survey on Graph Grammars, Proc. International Workshop on Graph Grammars and Their Applications to Computer Science and Biology, Bad Honnef 1978, this volume.
5. Rosenfeld, A.: Array and Web Languages: An Overview, in A. Lindenmayer/G. Rozenberg (Eds.): Automata, Languages, Development, 517–529, Amsterdam: North Holland 1976.