Firmansyah B, and Ali Umar. 2025. “Pengembangan Tes Diagnostik Two-Tier: Mengidentifikasi Pemahaman Konseptual Dan Prosedural Materi Prasyarat Struktur Aljabar Grup”. THEOREMA: The Journal Education of Mathematics 6 (2). https://e-journal.unimudasorong.ac.id/index.php/jurnaltheorema/article/view/4315.