@Article{ 
  servit,
  author = { Serra Cassano, Francesco and Vittone, Davide },
  title = { Graphs of bounded variation, existence and local boundedness of non-parametric minimal surfaces in Heisenberg groups },
  journal = { Adv. Calc. Var. },
  year = { 2014 },
  volume = { 7 },
  number = { 4 },
  pages = { 409--492 },
  URL = { http://cvgmt.sns.it/paper/1469/ },
  note = { cvgmt preprint}
}