@Misc{ 
  LeDNicSam15,
  author = { Le Donne, Enrico and Nicolussi Golo, Sebastiano and Sambusetti, Andrea },
  title = { Asymptotic behavior of the Riemannian Heisenberg group and its horoboundary },
  journal = {  },
  year = { 2015 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/2793/ },
  note = { cvgmt preprint}
}