Effect of the nearby levels on the resonance fluorescence spectrum of the atom–field interaction L. Villanueva-Vergara, F. Soto-Eguibar and H. M. Moya-Cessa Eur. Phys. J. Plus, 135 8 (2020) 614 Published online: 31 July 2020 DOI: 10.1140/epjp/s13360-020-00632-0