1. S. Arnborg, B. Courcelle, A. Proskurowski, D. Seese: An Algebraic Theory of Graph Reduction, Techn. Report 90-02, University Bordeaux (1990).
2. R. Arlt, M. Löwe, M. Röder: Basic Data Structures and Algorithms for Graph Grammar Implementations, Internal Technical Report, TU Berlin (1989).
3. M. Bauderon: Infinite Hypergraphs, to appear in: Theoretical Computer Science.
4. B. Courcelle: The Definability of Equational Graphs in Monadic 2nd Order Logic, in: ICALP'89, Springer, LNCS 372, 207–221 (1989).
5. B. Courcelle: The Monadic 2nd Order Logic of Graphs IV: Definability Properties of Equational Graphs, to appear in: Annals of Pure and Applied Logic.