Ravangjai, S., R. Kaewta, and T. Khampuang. “The Development of Mathematical Problem-Solving Ability in Statistics among Grade 7 Students through Project-Based Learning Combined with the STAD Cooperative Learning Technique”. Journal of Education Rajabhat Maha Sarakham University, vol. 23, no. 2, Aug. 2026, pp. 266-75, https://so06.tci-thaijo.org/index.php/edu-rmu/article/view/286317.