“STUDI PENENTUAN KANDUNGAN SULFUR (SULPHUR ANALYSIS) DALAM BATUBARA PADA PT GEOSERVICES SAMARINDA KALIMANTAN TIMUR”. Jurnal Geomine 2, no. 01 (August 31, 2015): 68–71. Accessed June 27, 2025. https://jurnal.fti.umi.ac.id/index.php/JG/article/view/1318.