@preprint{XN,
  abstract = {    },
  file = {xnBKX.pdf},
  fjournal = {},
  issn = {},
  number = {},
  year = {},
  url = {},
  mrclass = {},
  author = {Bars, Francesc and Kontogeorgis, Aristides and Xarles, Xavier},
  mrnumber = {},
  pages = {},
  volume = {},
  doi = {},
  journal = {},
  title = {Bielliptic and Hyperelliptic Modular curves X(N) and the group Aut(X(N)).}
}