Setyaningrum, Ika Rizky, and Palti Marulitua Sitorus. 2015. “Efficiency Measurement of Maintenance Costs on Customer Service Process PT Indonesia Comnets Plus West Java”. TRIKONOMIKA : Jurnal Ekonomi 14 (2):138-42. https://doi.org/10.23969/trikonomika.v14i2.411.