Prasertsri, N., A. Chareannukul, W. Tiyapan, Y. Leaungsomnapa, C. Wamalun, and S. Taptimhin. “The Study of Pain Management Index (PMI) in Older Patients with Cancer”. Nursing Journal of The Ministry of Public Health, vol. 34, no. 1, Apr. 2024, pp. 89-100, https://he02.tci-thaijo.org/index.php/tnaph/article/view/268981.