อ้วนพรมมา ว. “The Development of Mathematics Learning Activities Based on Constructivist Theory Emphasizing Polya’s Problem-Solving Processes On Probability for Mathayomsuksa 5”. Journal of Education Khon Kaen University (Graduate Studies Research), vol. 11, no. 4, May 2018, pp. 154-66, https://so02.tci-thaijo.org/index.php/EDGKKUJ/article/view/125463.