@Misc{ 
  van18,
  author = { van den Berg, Michiel },
  title = { Heat content in non-compact Riemannian manifolds },
  journal = { Integral Equations Operator Theory },
  year = { 2018 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/3758/ },
  note = { cvgmt preprint}
}