Tambunan, Lois. “Implementasi Pembelajaran Cooperative Learning Dan Locus of Control Dalam Meningkatkan Kemampuan Berpikir Kritis”. Jurnal Cendekia : Jurnal Pendidikan Matematika 5, no. 2 (April 17, 2021): 1051-1061. Accessed July 17, 2025. https://j-cup.org/index.php/cendekia/article/view/491.