Cosmology and the massive photon frequency shift in the Standard-Model ExtensionAlessandro D. A. M. Spallicci, José A. Helayël-Neto, Martín López-Corredoira and Salvatore CapozzielloEur. Phys. J. C, 81 1 (2021) 4DOI: https://doi.org/10.1140/epjc/s10052-020-08703-3