Ario, Marfi, Annajmi Annajmi, and Ratri Isharyadi. “Pengembangan Video Pembelajaran Kalkulus Diferensial Berbasis Pen Tablet”. Jurnal Cendekia : Jurnal Pendidikan Matematika 4, no. 2 (November 7, 2020): 1129-1142. Accessed January 18, 2021. https://j-cup.org/index.php/cendekia/article/view/363.