Matter power spectra in viable f(R) gravity models with dynamical background Yow-Chun Chen, Chao-Qiang Geng, Chung-Chi Lee and Hongwei Yu Eur. Phys. J. C, 79 2 (2019) 93 Published online: 30 January 2019 DOI: 10.1140/epjc/s10052-019-6613-y