จงเกียรติกาญจน์ พ. A LEADERSHIP DEVELOPMENT MODEL FOR MIDDLE MANAGEMENT OF PRIVATE SCHOOL UNDER UDON THANI EDUCATIONAL SERVICE AREA OFFICE 1. MCU SSR [Internet]. 2020 Apr. 24 [cited 2024 May 19];6(2-02):571-84. Available from: https://so03.tci-thaijo.org/index.php/jssr/article/view/242198