Entropy of the electrically charged hairy black holes Yu-Bo Ma, Li-Chun Zhang, Shuo Cao, Tonghua Liu, Shuaibo Geng, Yuting Liu and Yu Pan Eur. Phys. J. C, 78 9 (2018) 763 Published online: 22 September 2018 DOI: 10.1140/epjc/s10052-018-6254-6