Pentaquark states with the configuration in a simple model Shi-Yuan Li, Yan-Rui Liu, Yu-Nan Liu, Zong-Guo Si and Jing Wu Eur. Phys. J. C, 79 1 (2019) 87 Published online: 29 January 2019 DOI: 10.1140/epjc/s10052-019-6589-7