Najeeb N, Ahmad K, Yar S. A Hilfer Fractional Vaccination Epidemic Model: Stability Analysis and a Physics-Informed Neural Network Validated on COVID-19 Data. Int. Sci. Spectr. [Internet]. 2026 Sep. 13 [cited 2026 Oct. 13];:1-32. Available from: https://iscis-journal.org/index.php/iscis/article/view/21