Mohsen, Ahmed A., Hassan F. AL-Husseiny, Khalid Hattaf, and Bilal Boulfoul. 2021. “A Mathematical Model for the Dynamics of COVID-19 Pandemic Involving the Infective Immigrants”. Iraqi Journal of Science 62 (1): 295-307. https://doi.org/10.24996/ijs.2021.62.1.28.