A class of solitons in Maxwell-scalar and Einstein–Maxwell-scalar models Carlos A. R. Herdeiro, João M. S. Oliveira and Eugen Radu Eur. Phys. J. C, 80 1 (2020) 23 Published online: 11 January 2020 DOI: 10.1140/epjc/s10052-019-7583-9