Kusumastuti FA, Lutfi MK, Yusup Junaedi, Aliep. Epistemological Obstacle on Triangle And Quadrilateral Topic. JUPISI [Internet]. 2022 May 2 [cited 2026 Apr. 21];1(2). Available from: https://www.jupisi.untara.ac.id/index.php/jupisi/article/view/19