@Article{ 
  HeZha20,
  author = { He, Guoqing and Zhao, Peibiao },
  title = { The isoperimetric problemin the Heisenberg group $H^n$ with density },
  journal = { Analysis and Mathematical Physics },
  year = { 2020 },
  doi = { 10.1007/s13324-020-00367-2 },
  pages = { 23 },
  URL = { http://cvgmt.sns.it/paper/4775/ },
  note = { cvgmt preprint}
}