Ahmed, S., Hossain, M. M. and Khatun, U. S. (2014) “Pre-emptive analgesia : effect of low dose Ketamine as pre-emptive analgesia in postoperative pain management after lower abdominal surgery”, Journal of the Bangladesh Society of Anaesthesiologists, 17(1), pp. 17–22. doi: 10.3329/jbsa.v17i1.4046.