JAVED, T.; AHAD, B.; SINGH, P.; AHMAD, R. A prospective randomized study to compare tramadol and morphine for postoperative analgesia in spine surgeries using intravenous patient controlled analgesia. International Journal of Research in Medical Sciences, [S. l.], v. 5, n. 8, p. 3350–3354, 2017. DOI: 10.18203/2320-6012.ijrms20173140. Disponível em: https://www.msjonline.org/index.php/ijrms/article/view/3610. Acesso em: 15 oct. 2025.