Khumkongsuwan, Khanet, Sukanya Hajisalah, Anek Janjaroon, and Atchariya Watthanawisut. 2020. “A STUDY OF MATTHAYOMSUKSA II STUDENTS’ PROOF ABILITIES IN PARALLEL-LINES TOPICS VIA THE CONSTRUCTIVIST LEARNING MODEL (CLM)”. Journal of Industrial Education 19 (2):50-59. https://ph01.tci-thaijo.org/index.php/JIE/article/view/240523.