Yuliana, D., E. Dewi, and L. Zanthy. “Peningkatan Kemampuan Pemahaman Matematik Siswa SMP Menggunakan Pendekatan Project Based Learning”. Journal on Education, Vol. 1, no. 4, Aug. 2019, pp. 696-0, http://jonedu.org/index.php/joe/article/view/235.