Nasir, M, and Hazry Rafianto. “PENGARUH PENAMBAHAN SPONGE STEEL PADA SARINGAN KNALPOT TERHADAP EMISI GAS BUANG SEPEDA MOTOR EMPAT LANGKAH”. Ranah Research : Journal of Multidisciplinary Research and Development 1, no. 4 (July 19, 2019): 729 - 737. Accessed April 29, 2024. https://jurnal.ranahresearch.com/index.php/R2J/article/view/119.