(Apichit Ngamkom) PB. SYSTEMIC STUDENT LEADERSHIP DEVELOPMENT FOR ENHANCING LEARNER QUALITY: A CONCEPTUAL FRAMEWORK FOR SCHOOLS UNDER THE SECONDARY EDUCATIONAL SERVICE AREA OFFICE NAKHON SI THAMMARAT. JMND [internet]. 2026 Sep. 26 [cited 2026 Sep. 28];13(10):341-50. available from: https://so03.tci-thaijo.org/index.php/JMND/article/view/304661