Mohamad Pauzi Zakaria, et al. “APPLICATION OF PENTACYCLIC TRITERPANES AS A BIOMARKER IN IDENTIFYING THE SOURCE OF OIL POLLUTION IN THE EAST COAST OF PENINSULAR MALAYSIA”. PERINTIS EJournal, vol. 7, no. 2, Mar. 2021, pp. 95-110, https://perintis.org.my/ejournalperintis/index.php/PeJ/article/view/61.