Chantahong, Metawalai, Prapatsorn Pree-iam, and Arun Suikraduang. “The Development The Development of Problem-Based Learning Activities on Price Mechanisms in the Economy Economics Secondary for Grade 9”. Journal of Research and Development Institute Rajabhat Maha Sarakham University 8, no. 2 (November 8, 2021): 327–340. Accessed April 29, 2024. https://so03.tci-thaijo.org/index.php/rdirmu/article/view/252170.