A. Corradini, H. Ehrig, M. Löwe, U. Montanari, and F. Rossi. Dagstuhl Seminar on Graph Transformations in Computer Science, volume 776 of Lecture Notes in Computer Science, page 86-103. Springer, (1993)
U. Montanari, and F. Rossi. Dagstuhl Seminar on Graph Transformations in Computer Science, volume 776 of Lecture Notes in Computer Science, page 280-295. Springer, (1993)