เถาว์โท อ., and สราวุธ จ. “The Development of Learning Achievement in Topic of Solving Polynomial Fractional of Ninth Grade Students by Using Problem-Based Learning Approach”. Journal of Graduate School, Pitchayatat, Ubon Ratchathani Rajabhat University, vol. 13, no. 2, Dec. 2018, pp. 245-54, https://so02.tci-thaijo.org/index.php/Pitchayatat/article/view/221666.