@Article{ 
  bigvit08,
  author = { Bigolin, Francesco and Vittone, Davide },
  title = { Some remarks about parametrizations of intrinsic regular surfaces in the Heisenberg group },
  journal = { Publ. Mat. },
  year = { 2010 },
  volume = { 54 },
  number = { 1 },
  pages = { 159-172 },
  URL = { http://cvgmt.sns.it/paper/1489/ },
  note = { cvgmt preprint}
}