Janna, A. . “Development of a Self-directed Based on the Problem-based Learning Model to Promote Problem-solving Skills in Physics of Grade 10 Students on Mechanical Equilibrium”. Journal of Intellect Education, vol. 2, no. 4, Jan. 2024, pp. 21-37, https://so06.tci-thaijo.org/index.php/IEJ/article/view/270597.