Searching for hidden-charm baryonium signals in QCD sum rules Hua-Xing Chen, Dan Zhou, Wei Chen, Xiang Liu and Shi-Lin Zhu Eur. Phys. J. C, 76 11 (2016) 602 Published online: 04 November 2016 DOI: 10.1140/epjc/s10052-016-4459-0