Jaisook , Supaporn. 2024. “THE DEVELOPMENT OF A MATHEMATICAL PROBLEM SOLVING ABILITIES BY PROBLEM–BASED LEARNING APPROACHES FOR ELEMENTARY TEACHER STUDENTS”. Journal of MCU Nakhondhat 11 (11). Nakhon Si Thammarat, Thailand:170-80. https://so03.tci-thaijo.org/index.php/JMND/article/view/280931.