Darudiato, S., C. Novianto, H. Hendra, R. Reynaldo, and S. Selvi. “Membangun Customer Relationship Management Dalam Bisnis”. ComTech: Computer, Mathematics and Engineering Applications, vol. 2, no. 2, Dec. 2011, pp. 1350-8, doi:10.21512/comtech.v2i2.2962.