Nadhapat Bunnag และ Sumit Durongphongtorn. (2010) A comparison of epidural analgesic efficacy of tramadol-bupivacaine and morphine-bupivacaine combinations in dogs subjected to stifle surgery. Chulalongkorn University:ม.ป.ท.Nadhapat Bunnag และ Sumit Durongphongtorn. 2010. A comparison of epidural analgesic efficacy of tramadol-bupivacaine and morphine-bupivacaine combinations in dogs subjected to stifle surgery. ม.ป.ท.:Chulalongkorn University;Nadhapat Bunnag และ Sumit Durongphongtorn. A comparison of epidural analgesic efficacy of tramadol-bupivacaine and morphine-bupivacaine combinations in dogs subjected to stifle surgery. ม.ป.ท.:Chulalongkorn University, 2010. Print.