Manuel Clavel Francisco Durán Steven Eker Santiago Escobar Patrick Lincoln Narciso Martí-Oliet José Meseguer Carolyn L. Talcott Unification and Narrowing in Maude 2.4. 380-390 2009 RTA http://dx.doi.org/10.1007/978-3-642-02348-4_27 conf/rta/2009 db/conf/rta/rta2009.html#ClavelDEELMMT09