“Knowledge Level Relationship With Community Behavior Concerning Mask Use During The Covid-19 Pandemic In Langkat District, North Sumatera Province” (2021) Diagnosis Jurnal Ilmiah Kesehatan, 16(3), hlm. 141–146. Tersedia pada: https://ojs.institutnh.ac.id/index.php/jikd/article/view/474 (Diakses: 12 Oktober 2026).