@inproceedings{CADE-1988-Pfenning,
	author        = "Frank Pfenning",
	booktitle     = "{Proceedings of the Ninth International Conference on Automated Deduction}",
	doi           = "10.1007/BFb0012869",
	isbn          = "3-540-19343-X",
	pages         = "710--713",
	publisher     = "{Springer-Verlag}",
	series        = "{Lecture Notes in Computer Science}",
	title         = "{Single Axioms in the Implicational Propositional Calculus}",
	volume        = 310,
	year          = 1988,
}