@inproceedings{GG-1978-Ollongren,
	author        = "Alexander Ollongren",
	booktitle     = "{Proceedings of the First International Workshop on Graph-Grammars and Their Application to Computer Science and Biology}",
	doi           = "10.1007/BFb0025731",
	editor        = "Volker Claus and Hartmut Ehrig and Grzegorz Rozenberg",
	isbn          = "3-540-09525-X",
	pages         = "341--349",
	publisher     = "{Springer-Verlag}",
	series        = "{Lecture Notes in Computer Science}",
	title         = "{On Multilevel-Graph Grammars}",
	volume        = 73,
	year          = 1978,
}