Pannao, Namfon, and Urit Charoen-In. 2020. “THE DEVELOPMENT OF PROBLEM SOLVING ABILITY OF MATHAYOMSUKSA 5 STUDENTS BY USING METACOGNITION METHOD”. Journal of MCU Nakhondhat 7 (6). Nakhon Si Thammarat, Thailand:77-91. https://so03.tci-thaijo.org/index.php/JMND/article/view/244524.