Modelling and Simulating a Transmission of COVID-19 Disease: Niger Republic Case. European Journal of Pure and Applied Mathematics, Maryland, USA, v. 13, n. 3, p. 549–566, 2020. DOI: 10.29020/nybg.ejpam.v13i3.3727. Disponível em: https://www.ejpam.com/index.php/ejpam/article/view/3727. Acesso em: 5 dec. 2025.