Cosmology and the massive photon frequency shift in the Standard-Model Extension Alessandro D. A. M. Spallicci, José A. Helayël-Neto, Martín López-Corredoira and Salvatore Capozziello Eur. Phys. J. C, 81 1 (2021) 4 Published online: 05 January 2021 DOI: 10.1140/epjc/s10052-020-08703-3