DR ALOK PRATAP SINGH. 2015. “A COMPARATIVE STUDY OF INTRATHECAL BUPIVACAINE WITH BUPIVACAINETRAMADOL AND BUPIVACAINE-FENTANYL FOR POST-OPERATIVE PAIN RELIEF IN LOWER ABDOMINAL AND LOWER LIMB SURGERIES”. International Journal of Pharma and Bio Sciences 6 (4):752-58. https://ijpbs.net/index.php/journal/article/view/4664.