Kumar, Abhishake, Kumkum Gupta, Prashant K Gupta, Bhawana Rastogi, Bhanupriya Agrawal, and Pavitra Kalra. “Clinical Efficacy of Nalbuphine Versus Tramadol As Analgesic Adjuvant to Fentanyl During Major Abdominal Surgery Performed Under General Anesthesia- A Double Blind Randomized Study”. Academia Anesthesiologica International 4, no. 1 (May 10, 2019): 76-80. Accessed April 29, 2026. https://www.aijournals.com/index.php/aan/article/view/629.