Keiichirou Kusakari Masaki Nakamura Yoshihito Toyama Elimination Transformations for Associative-Commutative Rewriting Systems. 205-229 2006 37 J. Autom. Reasoning 3 http://dx.doi.org/10.1007/s10817-006-9053-y db/journals/jar/jar37.html#KusakariNT06