Siahaan, Ricki A., William A. Areros, and Sofia A. P. Sambul. 2020. “Kualitas Pelayanan Terhadap Kepuasan Pelanggan Kartu Halo Di PT. Telkomsel Grapari Cabang Manado”. Productivity 1 (4):350-54. https://ejournal.unsrat.ac.id/v3/index.php/productivity/article/view/30102.