Varghese, V., S. Bhoyar, and K. S. Nisar. “Analysis of Fractional-Order Model of COVID-19 Pandemics With a Nonlinear Incidence Rate”. Innovative Biosystems and Bioengineering, vol. 4, no. 3, Sept. 2020, pp. 160-7, doi:10.20535/ibb.2020.4.3.206271.