Scalar and vector perturbations in a universe with nonlinear perfect fluidEzgi Canay, Ruslan Brilenkov, Maxim Eingorn, A. Savaş Arapoğlu and Alexander ZhukEur. Phys. J. C, 81 3 (2021) 246DOI: https://doi.org/10.1140/epjc/s10052-021-09032-9