R, W., T. T, P. S, and S. B. “Determining the Minimum Number of Endotracheal Intubation Cases Necessary to Develop the Skills of Medical Students”. Chiang Mai Medical Journal, vol. 60, no. 3, July 2021, pp. 317-23, https://he01.tci-thaijo.org/index.php/CMMJ-MedCMJ/article/view/251883.