Summart, P., and N. Viriyapong. “Development of Mathematics Learning Activities Using KWDL Technique to Promote Mathematical Problem Solving Abilities and Learning Achievement on Percentage Problem Topic of Grade 6 Students”. Journal of Roi Et Rajabhat University, vol. 15, no. 1, Apr. 2021, pp. 75-86, https://so03.tci-thaijo.org/index.php/reru/article/view/240361.