Rahmad, Basuki Rahmad. “Sedimentasi Batubara Dan Karakteristik Mikroskopis Sulfur Batubara Daerah Sangatta, Kalimantan Timur ”. ReTII (October 28, 2020): 315-324. Accessed March 19, 2024. //journal.itny.ac.id/index.php/ReTII/article/view/2038.