On quasinormal modes in 4D black hole solutions in the model with anisotropic fluid S. V. Bolokhov and V. D. Ivashchuk Eur. Phys. J. C, 82 7 (2022) 624 Published online: 19 July 2022 DOI: 10.1140/epjc/s10052-022-10578-5