คูณทา จ., and พันธ์งาม อ. “A Development of Mathematics Reasoning Ability Through the Heuristics Thinking Model for Prathom Suksa 3 Students of Ban Nongkhun School under Ubon Ratchathani Primary Educational Service Area Office 3”. Ubon Ratchathani Journal of Research and Evaluation, vol. 2, no. 1, Aug. 2021, pp. 62-69, https://so06.tci-thaijo.org/index.php/ubonreseva/article/view/250839.