@inproceedings{FPCA-1989-Wadler,
	author        = "Philip Wadler",
	booktitle     = "{Proceedings of the Fourth Conference on Functional Programming Languages and Computer Architecture}",
	doi           = "10.1145/99370.99404",
	isbn          = "0-201-51389-7",
	pages         = "347--359",
	publisher     = "{ACM Press}",
	title         = "{Theorems for Free!}",
	year          = 1989,
}