“Comparison of Pre-emptive Use of Diclofenac, Ketorolac and Tramadol for Post-operative Pain in Laparoscopic Cholecystectomy”, j Bangladesh Soc Anaesthesiologists, vol. 20, no. 1, pp. 24–29, Dec. 2009, doi: 10.3329/jbsa.v20i1.4002.