Akrity Singh, & Harinandan Prasad. (2013). Comparative study of duration of analgesia with epidural bupivacaine & bupivacaine with tramadol in lower limb and lower abdominal surgeries. International Journal of Drug Delivery, 5(2), 239–244. Retrieved from https://ijdd.arjournals.org/index.php/ijdd/article/view/202