พรมตรุษ อัครพล, and ปุ่มสันเทียะ อุเทน. “Misconceptions and Mistakes in Mathematics on Inequality of Ninth Grade Students”. Journal of Education Studies 47, no. 4 (December 27, 2019): 539–561. Accessed May 20, 2024. https://so02.tci-thaijo.org/index.php/EDUCU/article/view/232138.