@inproceedings{LICS-1987-HarperHP,
	author        = "Robert Harper and Furio Honsell and Gordon D. Plotkin",
	booktitle     = "{Proceedings of the Second Symposium on Logic in Computer Science}",
	pages         = "194--204",
	publisher     = "{IEEE Computer Society}",
	title         = "{A Framework for Defining Logics}",
	year          = 1987,
}