Rinaldi, Erik, and Ekasatya Afriansyah. “Perbandingan Kemampuan Pemecahan Masalah Matematis Siswa Antara Problem Centered Learning Dan Problem Based Learning”. NUMERICAL: Jurnal Matematika dan Pendidikan Matematika 3, no. 1 (June 15, 2019): 9-18. Accessed February 25, 2020. https://journal.iaimnumetrolampung.ac.id/index.php/numerical/article/view/326.