ISPAWATI MALINTA; ANI M. HASAN; FRIDA M. YUSUF. PROBLEM BASED LEARNING MODEL VALIDITY TEST IN CLASS X ENVIRONMENTAL CHANGE MATERIALS. European Journal of Research Development and Sustainability, [S. l.], v. 3, n. 6, p. 77-81, 2022. Disponível em: https://scholarzest.com/index.php/ejrds/article/view/2317. Acesso em: 10 jan. 2025.