@Article{ 
  leomag10,
  author = { Leonardi, Gian Paolo and Magnani, Valentino },
  title = { Intersections of intrinsic submanifolds in the Heisenberg group },
  journal = { J. Math. Anal. Appl.  },
  year = { 2011 },
  volume = {  378 },
  number = { 1 },
  pages = { 98–108 },
  URL = { http://cvgmt.sns.it/paper/992/ },
  note = { cvgmt preprint}
}