Silitonga, Hotria Rosliana. “Efektivitas Model Pembelajaran Kooperatif Tipe Numbered Head Together Terhadap Kemampuan Pemecahan Masalah Matematis Siswa Kelas VII SMP Negeri 16 Medan”. Journal of Student Research 2, no. 2 (January 29, 2024): 56–66. Accessed January 23, 2026. https://ejurnal.stie-trianandra.ac.id/index.php/jsr/article/view/2777.