“Pengaruh Zat Aditif Urea Terhadap Kuantitas Biodiesel Pada Reaksi Transesterfikasi”. Jurnal Kimia Valensi 4, no. 1 (November 14, 2014). Accessed October 27, 2025. https://journal.uinjkt.ac.id/valensi/article/view/1049.