@Misc{ 
  CatMas16,
  author = { Catino, Giovanni and Mastrolia, Paolo },
  title = { Bochner type formulas for the Weyl tensor on four dimensional Einstein manifolds },
  journal = { Int. Math. Res. Not. },
  year = { 2018 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/3250/ },
  note = { cvgmt preprint}
}