Optical properties of an axially symmetric black hole in the Rastall gravityBakhtiyor Narzilloev, Ibrar Hussain, Ahmadjon Abdujabbarov and Bobomurat AhmedovEur. Phys. J. Plus, 137 5 (2022) 645DOI: https://doi.org/10.1140/epjp/s13360-022-02872-8