Sanansilp, Vimolluck, Varit Rasmidatta, Peerapatr Tangkitngamwong, and Santi Pongphantarak. 2006. “Comparison of Intravenous Vs. Intramuscular Morphine for Postoperative Pain Relief on the Multidisciplinary Care Path Implemented Ward”. Siriraj Medical Journal 58 (12):1216-21. https://he02.tci-thaijo.org/index.php/sirirajmedj/article/view/246012.