Ramdani, R. R. “Efisiensi Dan Biaya Operasional Excavator Hitachi EX 8000-6 Di Industri Pertambangan”. Natural Resources And Enviromental Management, vol. 3, no. 1, Feb. 2025, https://ejurnal.unikarta.ac.id/index.php/nrem/article/view/1821.