Results of preemptive epidural administration of morphine with or without bupivacaine in dogs and cats undergoing surgery: 265 cases (1997-1999) - Troncy, E; Junot, S; Keroack, S; Sammut, V; Pibarot, P; Genevois, JP; Cuvelliez, S (J Am Vet Med Assoc, 2002)