@Article{ 
  San17,
  author = { Santilli, Mario },
  title = { Fine properties of the curvature of arbitrary closed sets },
  journal = { Ann. Mat. Pura Appl. },
  year = { 2020 },
  doi = { 10.1007/s10231-019-00926-w },
  volume = { 199(2020) },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/4760/ },
  note = { cvgmt preprint}
}