MADZHAROVA, Iveta et al. Dynamic of SARS-CoV-2 spread in Bulgaria, 2020-2022. PROBLEMS of Infectious and Parasitic Diseases, Sofia, Bulgaria, v. 51, n. 1, p. 5–10, 2023. DOI: 10.58395/68gqp351. Disponível em: https://pipd.ncipd.org/index.php/pipd/article/view/51-1-1-Dynamic-of-SARS-CoV-2. Acesso em: 5 apr. 2025.