Probing an axial-vector tetraquark Zs via its semileptonic decay Zs X(4274) H. Sundu, B. Barsbay, S. S. Agaev and K. AziziEur. Phys. J. A, 54 7 (2018) 124DOI: https://doi.org/10.1140/epja/i2018-12552-0