@inproceedings{STOC-1977-HarelPS,
	author        = "David Harel and Amir Pnueli and Jonathan Stavi",
	booktitle     = "{Proceedings of the Ninth Annual ACM Symposium on Theory of Computing}",
	doi           = "10.1145/800105.803415",
	pages         = "249--260",
	publisher     = "{ACM}",
	title         = "{A Complete Axiomatic System for Proving Deductions about Recursive Programs}",
	year          = 1977,
}