Yi, Lin, Zhou Ying, and Tommy Wijaya. “The Trend of Mathematics Teaching Method Has Change From Fragments To Systematics”. Jurnal Cendekia : Jurnal Pendidikan Matematika 3, no. 2 (November 19, 2019): 471-480. Accessed July 8, 2020. https://j-cup.org/index.php/cendekia/article/view/137.