@article{RojasLeyva:20046N,
  author = "Rojas Leyva, Moises Porfirio  and  Carrion, Hector Leny  and  Toppan, Francesco",
  title = "{Residual Symmetries in the Presence of an EM Background}",
  doi = "10.22323/1.013.0041",
  journal = "PoS",
  year = 2004,
  volume = "WC2004",
  pages = "041"
}