Nuril Azizah, Rizky Wahyu. “Student’s Mathematical Concept Understanding Ability in the Material of Functions of Class XI of SMA Islam Sabilurrosyad Gasek Malang”. Pasundan Journal of Mathematics Education : Jurnal Pendidikan Matematika, vol. 15, no. 1, May 2025, pp. 81-92, https://journal.unpas.ac.id/index.php/pjme/article/view/20237.