Existence and Uniqueness of Solution for COVID-19 Model as an Application of Fractional Differential Equation. Academic Science Journal, [S. l.], v. 2, n. 1, p. 272–290, 2024. DOI: 10.24237/ASJ.02.01.711B. Disponível em: https://acadscij.uodiyala.edu.iq/index.php/Home/article/view/357. Acesso em: 5 apr. 2025.