สิงห์คำ น., ชมภูคำ ว. and ชมภูคำ พ. 2018. Development of Mathematics Activity Through Cooperative Learning with the Geometer’s Sketchpad Program to Encourage Learning Achievement and Creative Thinking Skills of Mathayomsuksa 2 Students. Journal of Graduate Research. 9, 2 (Dec. 2018), 1–20.