“AROMATIC BIOMARKER FROM BROWN COAL, SANGATTA COALFIELD, EAST BORNEO OF MIDDLE MIOCENE TO LATE MIOCENE AGE”. Jurnal Teknologi (Sciences & Engineering) 78, no. 6 (May 30, 2016). Accessed April 2, 2025. https://journals.utm.my/jurnalteknologi/article/view/8822.