@inproceedings{LICS-1999-Simpson,
	author        = "Alex K. Simpson",
	booktitle     = "{Proceedings of the 14th Annual IEEE Symposium on Logic in Computer Science}",
	doi           = "10.1109/LICS.1999.782592",
	isbn          = "0-7695-0158-3",
	pages         = "77--85",
	publisher     = "{IEEE Computer Society}",
	title         = "{Elementary Axioms for Categories of Classes}",
	year          = 1999,
}