annor, Alfi. “Identification of Difficulty in Resolving Problem Trigonometric Functions Limit in Class XI MA PIP (Islamic Education Parigi) Central of Habirau”. Jurnal PTK dan Pendidikan 2, no. 2 (November 23, 2016). Accessed May 2, 2024. https://jurnal.uin-antasari.ac.id/index.php/ptkpend/article/view/1025.