The generalized cosmic equation of state: a revised study with cosmological standard rulersYubo Ma, Jia Zhang, Shuo Cao, Xiaogang Zheng, Tengpeng Xu and Jingzhao QiEur. Phys. J. C, 77 12 (2017) 891DOI: https://doi.org/10.1140/epjc/s10052-017-5461-x