Consistency between dynamical and thermodynamical stabilities for perfect fluid in f(R) theories Xiongjun Fang, Xiaokai He and Jiliang Jing Eur. Phys. J. C, 78 8 (2018) 623 Published online: 04 August 2018 DOI: 10.1140/epjc/s10052-018-6053-0