Muons in air showers at the Pierre Auger Observatory: mean number in highly inclined events [Phys. Rev. D 91, 032003 (2015)] Publisher ’ s Note - Aab, A.; Albuquerque, Ivone Freire da Mota e; Souza, Vitor de; Gouffon, Philippe; Prado, R. R.; Santos, Edivaldo Moura; Peixoto, Carlos Jose Todero (Physical Review D, 2015)