Accretion disc around black hole in Einstein-SU(N) non-linear sigma model G. Abbas, Hamza Rehman, M. Usama and Tao Zhu Eur. Phys. J. C, 83 5 (2023) 422 Published online: 21 May 2023 DOI: 10.1140/epjc/s10052-023-11600-0