Pratama, P. R., M. Tapilouw, and E. Retnaningrum. “Pengaruh Penerapan Metode Guided Discovey Learning Terhadap Peningkatan Kemampuan Observasi Matematis Pada Siswa”. EDUCARE, vol. 11, no. 2, Dec. 2013, pp. 20-27, https://jurnal.fkip.unla.ac.id/index.php/educare/article/view/184.