Gultom DM, Hasibuan EE, Sari E, Batubara FLE. The Relationship between Knowledge and Attitude of the Elderly in Handwashing as an Effort to Prevent Covid-19 . Int Jou of PHE [Internet]. 2022 Jan. 27 [cited 2024 Nov. 25];1(1):56-9. Available from: https://ejournal.ipinternasional.com/index.php/ijphe/article/view/13