Yannarut, Pitiya, Wandee Kasemsukpipat, and Tongta Somchaipeng. “A Study of Mathematical Concept of Mathayomsuksa 3 Students by Using a Concept Attainment Model”. Humanities and Social Sciences Journal of Pibulsongkram Rajabhat University 16, no. 2 (September 30, 2022): 726–738. Accessed May 8, 2024. https://so01.tci-thaijo.org/index.php/GraduatePSRU/article/view/244291.