Thaklowa, C., and W. . Amatariyakul. “The Guideline of Transformational Leadership Development Administrators under Secondary Educational Service Area Office 21”. Rajapark Journal, vol. 15, no. 41, July 2021, pp. 310-25, https://so05.tci-thaijo.org/index.php/RJPJ/article/view/250934.