Hartono, Billie Ariyanta, and Aloysius Gunadi Brata. “Determinants of Indonesian Nickel Exports: Panel Data Analysis Using Gravity Model Approach”. Jurnal Ilmu Ekonomi Terapan 10, no. 1 (June 29, 2025): 112–121. Accessed June 30, 2025. https://e-journal.unair.ac.id/JIET/article/view/65522.