Shehu Sidi A, Mohd MH. Bifurcation Analysis of a Modified SIR-Based COVID-19 Model with Nonlinear Incidence and Recovery Rates. MATEMATIKA [Internet]. 2025 Nov. 15 [cited 2025 Nov. 19];41(3):375-87. Available from: https://matematika.utm.my/index.php/matematika/article/view/1703