@inproceedings{ICALP-1990-Schwartzbach,
	author        = "Michael I. Schwartzbach",
	booktitle     = "{Proceedings of the 17th International Colloquium on Automata, Languages and Programming}",
	doi           = "10.1007/BFb0032020",
	isbn          = "3-540-52826-1",
	pages         = "32--45",
	publisher     = "{Springer-Verlag}",
	series        = "{Lecture Notes in Computer Science}",
	title         = "{Static Correctness of Hierarchical Procedures}",
	volume        = 443,
	year          = 1990,
}