Kongtoei, Khamporn, Samoot Chamnan, and Sataporn Pruettikul. 2018. “Development of Ethical Leadership Indicators for School Principals Under Bangkok Metropolitan Administration”. Academic Journal of Thailand National Sports University 10 (2). Chonburi, Thailand:237-50. https://he02.tci-thaijo.org/index.php/TNSUJournal/article/view/248640.