Complex dynamics of a fractional-order delayed epidemic model incorporating waning immunity and optimal controlSuvankar Majee, Soovoojeet Jana, T. K. Kar and Bidhan BhuniaEur. Phys. J. Spec. Top., 234 8 (2025) 1823-1850DOI: https://doi.org/10.1140/epjs/s11734-024-01221-3