Santoso , Daniel Albert, and Agustinus Wijaya. “Grapari Information Technology Service Analysis of Telkomsel Salatiga Using ITIL V3 Domain Service Operation”. Journal of Information Technology Ampera 1, no. 3 (December 20, 2020): 144–154. Accessed June 24, 2024. https://journal-computing.org/index.php/journal-ita/article/view/30.