@inproceedings{PLILP-1991-ProiettiP,
	author        = "Maurizio Proietti and Alberto Pettorossi",
	booktitle     = "{Proceedings of the Third International Symposium on Programming Language Implementation and Logic Programming}",
	doi           = "10.1007/3-540-54444-5_111",
	isbn          = "3-540-54444-5",
	note          = "long version: TCS 142(1): 89-124 (1995)",
	pages         = "347--358",
	publisher     = "{Springer-Verlag}",
	series        = "{Lecture Notes in Computer Science}",
	title         = "{Unfolding — Definition — Folding, in this Order, for Avaoiding Unnecessary Variables in Logic Programs}",
	volume        = 528,
	year          = 1991,
}