Rahmawati, Isadora, and Dermawan Wibisono. 2025. “Proposed Improvements of Air Conditioner Preventive Maintenance In The Coal Mining Industry By Utilizing DMAIC Methodology ”. Dinasti International Journal of Education Management and Social Science 7 (1):1073-86. https://doi.org/10.38035/dijemss.v7i1.5555.