Widiyanto, Aris, Joko Tri Atmojo, and Rina Tri Handayani. 2021. “Trend Analysis of the Mobile Health COVID-19 Application As A Preventive Strategy in the Era of COVID-19 Pandemic in Surakarta”. Journal of Health Promotion and Behavior 6 (2):104-11. https://thejhpb.com/index.php/thejhpb/article/view/314.