1. Andries, M., Engels, G., Rekers, J.: How to represent a Visual Program? In: [TVL 1996] (1996)
2. Bardohl, R.: GenGEd - A Generic Graphical Editor for Visual Languages based on Algebraic Graph Grammars. In: [VL 1998], pp. 48–55 (1998)
3. Bardohl, R., Taentzer, G.: Defining Visual Languages by Algebraic Specification Techniques and Graph Grammars. In: [TVL 1997], pp. 27–42 (1997)
4. Costagliola, G., De Lucia, A., Orefice, S., Tortora, G.: A Framework of Syntactic Models for the Implementation of Visual Languages. In: [VL 1997], pp. 58–65 (1997)
5. Lecture Notes in Computer Science;A. Corradini,1996