@Misc{ 
  Pis20a,
  author = { Piscitelli, Gianpaolo },
  title = { Convex Symmetrization for Anisotropic Elliptic Equations with a lower
  order term },
  journal = {  },
  year = { 2020 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/5700/ },
  note = { cvgmt preprint}
}