Poonchu, P., and S. Darbavasu. “Characteristics of Professional Administrators Affecting the Efficiency of Private School Management under the Samut Prakan Provincial Education Office”. Journal of Humanities and Social Sciences, Rajapruk University, vol. 7, no. 2, Aug. 2021, pp. 156-69, https://so03.tci-thaijo.org/index.php/rpu/article/view/254783.