Aart Middeldorp Taro Suzuki Mohamed Hamada Complete Selection Functions for a Lazy Conditional Narrowing Calculus. 2002 2002 Journal of Functional and Logic Programming http://danae.uni-muenster.de/lehre/kuchen/JFLP/articles/2002/S02-01/JFLP-A02-03.pdf db/journals/jflp/jflp2002.html#MiddeldorpSH02