@Article{ 
  PraSar18,
  author = { Pratelli, Aldo and Saracco, Giorgio },
  title = { On the isoperimetric problem with double density },
  journal = { Nonlinear Anal. },
  year = { 2018 },
  doi = { 10.1016/j.na.2018.04.009 },
  volume = { 177 },
  number = { B },
  pages = { 733--752 },
  URL = { http://cvgmt.sns.it/paper/3842/ },
  note = { cvgmt preprint}
}