OGUNMODIMU, M. .; YUSUF, T. .; OLOTU, O. . Sensitivity and stability analyses of COVID-19 model with waning immunity and relapse: a case study of Nigeria. International Journal of Mathematical Analysis and Modelling, [S. l.], v. 8, n. 1, 2025. Disponível em: https://tnsmb.org/journal/index.php/ijmam/article/view/220. Acesso em: 28 jul. 2026.