“Karakteristik Mineraloid Opal Limbong, Kabupaten Luwu Utara, Provinsi Sulawesi Selatan”. Jurnal Geomine 8, no. 03 (December 31, 2020): 220–227. Accessed June 27, 2025. https://jurnal.fti.umi.ac.id/index.php/JG/article/view/1409.