Sitanggang, Derma. “Analisis Kesulitan Siswa Memahami Konsep, Prinsip, Dan Prosedur Pada Soal-Soal Materi Garis Dan Sudut”. Journal of Student Research 2, no. 2 (January 26, 2024): 31–46. Accessed May 12, 2026. https://scientivapress.org/index.php/jsr/article/view/2752.