Tavis-Cummings models and their quasi-exactly solvable Schrödinger Hamiltonians T. Mohamadian, J. Negro, L. M. Nieto and H. Panahi Eur. Phys. J. Plus, 134 7 (2019) 363 Published online: 29 July 2019 DOI: 10.1140/epjp/i2019-12753-4