Shah, H. A.; B., J. S.; Bhavsar, M. A Comparative Study of Oral Tapentadol With Thoracic Epidural Analgesia Versus Intravenous Tramadol and Paracetamol Combination for Postoperative Analgesia in off Pump CABG. Int J Basic Clin Pharmacol 2017, 2, 723-727.