Upontean , Suttipong, and Kritsakorn Onlamul. “Problem-Based Learning Management for Developing Desirable Characteristics in Junior High School Students: A Mixed-Methods Research and Development Study in Maha Sarakham Province, Thailand”. Insights into Modern Education (i-ME) 3, no. 1 (April 9, 2025): 1–20. accessed September 12, 2026. https://so19.tci-thaijo.org/index.php/IME/article/view/2274.