ARLIANSYAH MAULANA. Teori Perkembangan Kognitif Piaget Pada Tahap Operasional Formal. Al-Ahnaf: Journal of Islamic Education, Learning and Religious Studies , [S. l.], v. 1, n. 1, p. 12–21, 2024. DOI: 10.61166/ahnaf.v1i1.7. Disponível em: https://al-ahnaf.my.id/index.php/i/article/view/7. Acesso em: 23 sep. 2025.