RUSTANDI, Ino. The Effect of Soft Skills-Based Group Investigation Model on Mathematical Problem Solving Ability and Self- Confidence of Secondary School Student. Pasundan Journal of Mathematics Education : Jurnal Pendidikan Matematika, [S. l.], v. 15, n. 2, p. 116–131, 2025. Disponível em: https://journal.unpas.ac.id/index.php/pjme/article/view/32896. Acesso em: 8 jan. 2026.