กุมภิโร พ., กำจัดภัย ส., & ชำนาญกิจ พ. (2018). Development of an Enrichment Curriculum According to the Concepts of Context-based Learning through the Use of Problem-based Learning for Enhancing Mathematical Skills and Processes for Sixth Grade Students. Journal of Graduate School, Pitchayatat, Ubon Ratchathani Rajabhat University, 13(2), 127–135. Retrieved from https://so02.tci-thaijo.org/index.php/Pitchayatat/article/view/221641