Justice Panggabean, Melania, Yulita Molliq Rangkuti, and Ichwanul Muslim Karo-Karo. “Design of a Geographic Information System (gis) for the Spread of Covid-19 Disease in Medan City”. Jurnal Mantik 6, no. 4 (February 28, 2023): 3726-3736. Accessed June 26, 2026. https://www.ejournal.iocscience.org/index.php/mantik/article/view/3437.