@inproceedings{LICS-1990-FreydMRS,
	author        = "Peter J. Freyd and P. Mulry and Giuseppe Rosolini and Dana S. Scott",
	booktitle     = "{Proceedings of the Fifth Annual Symposium on Logic in Computer Science}",
	doi           = "10.1109/LICS.1990.113760",
	isbn          = "0-8186-2073-0",
	pages         = "346--354",
	publisher     = "{IEEE Computer Society}",
	title         = "{Extensional PERs}",
	year          = 1990,
}