Mujab, Shokhibul, et al. “Analysis of Valve Clearance Variation Effects on Exhaust Gas Opacity in Biosolar-Fueled Mitsubishi L300 Diesel Engine”. Jurnal Perintis: Pengembangan Riset Inovatif Teknik, Teknologi, Dan Sains, vol. 2, no. 1(Januari-Februari), Feb. 2026, https://ejournal.pktj.ac.id/index.php/perintis/article/view/42-47.