Kong, Fanchao, and Juan J. Nieto. “Impact of Discontinuous Treatments on the Generalized Epidemic Model”. Topological Methods in Nonlinear Analysis 56, no. 1 (August 29, 2020): 349–378. Accessed July 22, 2024. https://apcz.umk.pl/TMNA/article/view/TMNA.2020.018.