@inproceedings{ICALP-1981-EngelfrietF,
	author        = "Joost Engelfriet and Gilberto Filé",
	booktitle     = "{Proceedings of the Eighth Colloquium on Automata, Languages and Programming}",
	doi           = "10.1007/3-540-10843-2_16",
	isbn          = "3-540-10843-2",
	pages         = "193--207",
	publisher     = "{Springer-Verlag}",
	series        = "{Lecture Notes in Computer Science}",
	title         = "{Passes, Sweeps and Visits}",
	volume        = 115,
	year          = 1981,
}