Stephani cosmology: entropically viable but observationally challenged Yen Chin Ong, S. Sedigheh Hashemi, Rui An and Bin Wang Eur. Phys. J. C, 78 5 (2018) 405 Published online: 23 May 2018 DOI: 10.1140/epjc/s10052-018-5866-1