Strong gravitational lensing around Kehagias–Sfetsos compact objects surrounded by plasma Sudipta Hensh, Jan Schee, Ahmadjon Abdujabbarov and Zdeněk Stuchlík Eur. Phys. J. Plus, 137 2 (2022) 242 Published online: 18 February 2022 DOI: 10.1140/epjp/s13360-022-02454-8