@Article{ 
  Mag15a,
  author = { Magnani, Valentino },
  title = { Some remarks on densities in the Heisenberg group },
  journal = { Ann. Acad. Sci. Fenn. Math. },
  year = { 2017 },
  volume = { 42 },
  number = { 1 },
  pages = { 357–365 },
  URL = { http://cvgmt.sns.it/paper/2792/ },
  note = { cvgmt preprint}
}