@InProceedings{FerStiS_j1997, author = {Henning~Fernau and Ralf~Stiebe}, title = {Regulations by Valences}, booktitle = {Mathematical Foundations of Computer Science 1997, 22nd International Symposium, MFCS'97, Bratislava, Slovakia, August 25--29, 1997, Proceedings}, year = {1997}, pages = {239--248}, editor = {Igor~Pr\'{\i}vara and Peter Ruzicka}, publisher = springer, series = {LNCS}, volume = 1295 }