RISANO, yudi. Utilization of Natural Zeolites and Fly Ash (Coal) Mixture Physically Activated Using Furnace As A Pellet - shaped Air Filter To Increase Engine Torque, Tecumseh TD110. 4-Stroke Petrol Motor. Journal of Engineering and Scientific Research, [S. l.], v. 4, n. 1, p. 14–17, 2022. DOI: 10.23960/jesr.v4i1.99. Disponível em: https://jesr.eng.unila.ac.id.121-50-32-50.cpanel.site/index.php/ojs/article/view/99. Acesso em: 15 jan. 2026.