Nagarjuna Thakur, Ravikanth Pula and Ravichandra Raya 2019. Effect of Preoperative Ketamine and Magnesium Sulfate on Intra & Postoperative Analgesia in Laparoscopic Cholecystectomy: A Comparative Randomized Controlled Study. Academia Anesthesiologica International. 4, 2 (Dec. 2019), 281-287. DOI:https://doi.org/10.21276/aan.2019.4.2.63.