A Comparison of the Variable-Abstraction and Constant-Abstraction Methods for Associative-Commutative Unification.

Mark E. Stickel A Comparison of the Variable-Abstraction and Constant-Abstraction Methods for Associative-Commutative Unification. 285-289 1987 3 J. Autom. Reasoning 3 db/journals/jar/jar3.html#Stickel87