Ayumni, Febi, Himmatul Ulya, and Sumaji Sumaji. “A Comparison of Student’s Mathematical Problem-Solving Ability Between Realistic Mathematics Education Assisted by GeoSpace and Direct Instruction”. Kognitif: Jurnal Riset HOTS Pendidikan Matematika 5, no. 4 (December 30, 2025). Accessed January 9, 2026. https://etdci.org/journal/kognitif/article/view/3340.