Pontoh, Adel. “Penerapan Metode Problem Solving Learning Pada Pelajaran Ekonomi Materi Pendapatan Nasional Pada Siswa Kelas XI SMAN 5 Kabupaten Halmahera Utara”. Jurnal Ilmiah Wahana Pendidikan 9, no. 21 (November 30, 2023): 1174-1189. Accessed July 17, 2026. https://jurnal.peneliti.net/index.php/JIWP/article/view/8644.