Sidik, Geri Syahril, Riza Fatimah Zahrah, Mimi Hariyani, and Fadhilaturrahmi Fadhilaturrahmi. “Development of Mathematics Teaching Materials Using Didactical Design Research: A Study on Enhancing Pedagogical Content Knowledge in Quadratic Inequalities”. Journal of Education For Sustainable Innovation 1, no. 1 (July 29, 2023): 39–48. Accessed September 19, 2025. https://ejournal.papanda.org/index.php/jesi/article/view/489.