Phothisa, Bandit, and Paisarn Worakham. “The Development of Problem-Based Learning Activities to Promote Science Process Skills of Grade 1 Students”. Journal of Education Rajabhat Maha Sarakham University 21, no. 2 (August 29, 2024): 39–48. accessed December 8, 2025. https://so06.tci-thaijo.org/index.php/edu-rmu/article/view/264484.