Remarks on the heavy-quark flavour symmetry for doubly heavy hadronic molecules V. Baru, E. Epelbaum, J. Gegelia, C. Hanhart, U.-G. Meißner and A. V. Nefediev Eur. Phys. J. C, 79 1 (2019) 46 Published online: 21 January 2019 DOI: 10.1140/epjc/s10052-019-6560-7