X(3872) and its heavy quark spin symmetry partners in QCD sum rulesHalil Mutuk, Yasemin Saraç, Hasan Gümüş and Altuğ ÖzpineciEur. Phys. J. C, 78 11 (2018) 904DOI: https://doi.org/10.1140/epjc/s10052-018-6382-z