@inproceedings{ICALP-1998-Pitts,
	author        = "Andrew M. Pitts",
	booktitle     = "{Proceedings of the 25th International Colloquium on Automata, Languages and Programming}",
	doi           = "10.1007/BFb0055063",
	isbn          = "3-540-64781-3",
	pages         = "309--326",
	publisher     = "{Springer-Verlag}",
	series        = "{Lecture Notes in Computer Science}",
	title         = "{Existential Types: Logical Relations and Operational Equivalence}",
	volume        = 1443,
	year          = 1998,
}