@article{PatersonRA:debruijn,
	title = "De {Bruijn} Notation as a Nested Datatype",
	author = "Richard Bird and Ross Paterson",
	url = "http://www.soi.city.ac.uk/~ross/papers/debruijn.html",
	journal = "Journal of Functional Programming",
	volume = 9,
	number = 1,
	pages = "77-91",
	month = Jan,
	year = 1999
}