Donpudsa, P., and T. . Khechornphak. “The Development Of Learning Achievement on Parallel Lines By Group Learning Activity With TAI Technique of Mathayomsuksa 2”. Journal of Education Rajabhat Maha Sarakham University, vol. 19, no. 1, May 2022, pp. 131-40, https://so06.tci-thaijo.org/index.php/edu-rmu/article/view/256457.