@inproceedings{ICALP-1972-Reghizzi,
	author        = "Stefano Crespi-Reghizzi",
	booktitle     = "{Proceedings of the Colloquium on Automata, Languages and Programming}",
	isbn          = "0-7204-2074-1",
	pages         = "367--376",
	title         = "{Approximation of Phrase Markers by Regular Sets}",
	year          = 1972,
}