R. Jayananthan, M. C. Maheswari, K. Krishnan. “Local Stability Analysis of Delayed Seir Model”. Mathematical Statistician and Engineering Applications 71, no. 4 (September 12, 2022): 2371–2382. Accessed July 29, 2026. https://philstat.org/index.php/MSEA/article/view/790.