Batubara, Heppy Jelita Sari. “Relationship Level Of Community Knowledge About Covid-19 Vaccination On Covid-19 Events In Polonia Medan Puskesmas 2021-2022”. Science Midwifery 10, no. 3 (July 29, 2022): 2001–2007. Accessed May 1, 2026. https://www.midwifery.iocspublisher.org/index.php/midwifery/article/view/581.