Mekarkakorn, T., S. Narkwiboonwong, and W. Suthinarak. “A Causal Model Development of Professional Teachers in Vocational Education”. Kasetsart Journal of Social Sciences, vol. 40, no. 2, Aug. 2019, pp. 509-18, https://so04.tci-thaijo.org/index.php/kjss/article/view/242214.