Siahaan, Yuni Hariati, Syarifah Nur Siregar, and Atma Murni. “Implementation of Problem-Based Learning Model to Improve Mathematical Problem-Solving Skills of Grade XI-2 Students of SMAN 19 Pekanbaru”. Jurnal Didactical Mathematics 8, no. 1 (April 30, 2026): 204–222. Accessed June 18, 2026. https://www.ejournal.unma.ac.id/index.php/dm/article/view/17437.