Nunkaew, S., and M. Channarong. “Factors Affecting Postoperative Complications in the Elderly Patients undergoing Surgery in Sichon Hospital, Nakhon Si Thammarat Province”. Region 11 Medical Journal, vol. 37, no. 4, Dec. 2023, pp. 44-57, https://he02.tci-thaijo.org/index.php/Reg11MedJ/article/view/265779.