Sitinjak, S., and M. Idris. “Experimental Study of Density and Iodine Number of Biodiesel in Production from Waste Cooking Oil”. IRA Jurnal Teknik Mesin Dan Aplikasinya (IRAJTMA), vol. 3, no. 1, Apr. 2024, pp. 66-71, doi:10.56862/irajtma.v3i1.100.