OTP RG Yehezkiel, Maulana Yusuf, Muhammad Rendana, Eddy Ibrahim and Syamsul Komar 2026. Analysis of the Effect of Total Sulfur on Coal Loss due to Spontaneous Combustion at Stockpile 1, Air Laya Mine, PT Bukit Asam Tbk. ARMADA : Jurnal Penelitian Multidisiplin. 4, 8 (Aug. 2026), 4432–4441.