1. N. ABE, M. Mizumoto, J. Toyoda AND H. Tanaka Web Grammars and Several Graphs. Journal of Computer and System Sciences 7, 37–65. 1973.
2. G. Rozenserg (Ed.)Handbook of Graph Grammars and Computing by Graph Transformation, Volume 1: Foundations World Scientific, 1997.
3. R. González and M. ThomasonSyntactic Pattern Recognition. An Introduction. Addison-Wesley Publishing Company. 1978.
4. J. Hopcroft, J. UllmanIntroduction to Automata Theory, Languages and Computation. Addison-Wesley Publishing Company. 1979.
5. D. López Inferencia de Gramáticas de Grafos para una tarea de Reconocimiento de Dígitos Manuscritos. Technical Report, DSIC-II/34/97 Departamento de Sistemas Informáticos y Computación, Polytechnic University of Valencia. September 1997.