H. Ehrig, and H. Kreowski. Category Theory Applied to Computation and Control, volume 25 of Lecture Notes in Computer Science, page 144-150. Springer, (1974)
H. Ehrig, W. Kühnel, and M. Pfender. Category Theory Applied to Computation and Control, volume 25 of Lecture Notes in Computer Science, page 137-143. Springer, (1974)
H. Ehrig, and B. Rosen. Graph-Grammars and Their Application to Computer Science and Biology, volume 73 of Lecture Notes in Computer Science, page 192-205. Springer, (1978)
H. Ehrig, and A. Liedtke. Graph-Grammars and Their Application to Computer Science and Biology, volume 73 of Lecture Notes in Computer Science, page 206-223. Springer, (1978)