Loka Andari, Ida Ayu Ketut Manik, I Wayan Darsana, dan Agung Sri Asri. “Pengaruh Model Problem Based Learning (PBL) Berbasis Portofolio Terhadap Hasil Belajar IPS”. International Journal of Elementary Education 3, no. 4 (Oktober 10, 2019): 373–380. Diakses Mei 18, 2024. https://ejournal.undiksha.ac.id/index.php/IJEE/article/view/21309.