Kurnia Putri, Anggi, et al. “The Effect of Problem-Based Learning Using Geoboard on Cognitive Ability of SDN 8 Mamboro Students”. Media Pendidikan Matematika, vol. 13, no. 2, Dec. 2025, pp. 822-31, https://ojspanel.undikma.ac.id/index.php/jmpm/article/view/17822.