An Addition of Ethanol and Patchouli Oil on Pertamax: The Case Study of Their Effect on Exhaust Gas Emission for 4-stroke Engine. Jurnal Teknik Mesin Mechanical Xplore, [S. l.], v. 3, n. 2, p. 87–95, 2022. DOI: 10.36805/jtmmx.v3i2.2975. Disponível em: https://journal.ubpkarawang.ac.id/index.php/JTMMX/article/view/2975. Acesso em: 25 aug. 2025.