I Wayan Angga Widianta Putra, I. G. K. Sukadana, I Gusti Ngurah Putu Tenaya, and I Putu Widiarta, “The Effect of Types of Biogas and Methanol Purification and Loading as Fuel for Four-Stroke Generators on Exhaust Emissions”, Nat Sci Eng Tech Jour, vol. 3, no. 2, pp. 200-205, Mar. 2023.