T. A. Efimova, I. A. Timoshchenko, and N. G. Abrashina-Zhadaeva, “Fractional differential model of the spread of COVID-19”, Журнал Белорусского государственного университета. Физика, no. 3, pp. 40–48, Oct. 2021, doi: 10.33581/2520-2243-2021-3-40-48.