Nasution, F. A., M. M. Amin, and E. Effendy. “Factors Associated With Smartphone Addiction During COVID-19 Pandemic Lockdown in Students of Faculty of Medicine in North Sumatera”. Open Access Macedonian Journal of Medical Sciences, vol. 10, no. T7, Mar. 2022, pp. 59-62, doi:10.3889/oamjms.2022.9257.