Use of Some Topological Concepts in the Study of Some COVID-19 Symptoms. European Journal of Pure and Applied Mathematics, Maryland, USA, v. 13, n. 4, p. 852–860, 2020. DOI: 10.29020/nybg.ejpam.v13i4.3819. Disponível em: https://www.ejpam.com/index.php/ejpam/article/view/3819. Acesso em: 2 apr. 2025.