Fractal-fractional order dynamical behavior of an HIV/AIDS epidemic mathematical model Zeeshan Ali, Faranak Rabiei, Kamal Shah and Touraj Khodadadi Eur. Phys. J. Plus, 136 1 (2021) 36 Published online: 04 January 2021 DOI: 10.1140/epjp/s13360-020-00994-5