Thienthong, Somboon. 2019. “Clinical Guidance for Acute Postoperative Pain Management 2019 The Royal College of Anesthesiologists of Thailand (RCAT) and The Thai Association for the Study of Pain (TASP) : Second Edition”. Thai Journal of Anesthesiology 46 (1):47-70. https://he02.tci-thaijo.org/index.php/anesthai/article/view/228095.