A. Haris Nasution, M. Rasyid Harahap, S. Napid, and M. Rafiq Yanhar, “Machinability Study of Cast Iron in Small and Medium Enterprise”, IJET, vol. 7, no. 3.14, pp. 445–448, Jul. 2018, doi: 10.14419/ijet.v7i3.14.25781.