Reskina, Sehatta Saragih, Elfis Suanto, and Maimunah. “Student Errors Analysis Problem-Solving Based Castolan Theory on Relations and Functions Material”. Numerical: Jurnal Matematika dan Pendidikan Matematika 7, no. 1 (June 20, 2023): 157–166. Accessed August 24, 2025. https://journal.iaimnumetrolampung.ac.id/index.php/numerical/article/view/2895.