Izzah Khalif Raihan, Sinar Ayu Wulandari, and Zainal Abidin Achmad. “Business Competition Related to the Rapid Test Service for Diagnosis of COVID-19 in Hospitals in Surabaya, Indonesia”. Journal of Peace, Development and Communication, vol. 5, no. 04, Dec. 2021, pp. 48-62, http://pdfpk.net/ojs/index.php/jpdc/article/view/282.