An Addition of Ethanol and Patchouli Oil on Pertamax: The Case Study of Their Effect on Exhaust Gas Emission for 4-stroke Engine. JTMMX [Internet]. 31 Desember 2022 [dikutip 25 Agustus 2025];3(2):87-95. Tersedia pada: https://journal.ubpkarawang.ac.id/index.php/JTMMX/article/view/2975