@Article{ 
  CatRonVez19,
  author = { Catino, Giovanni and Roncoroni, Alberto and Vezzoni, Luigi },
  title = { On the umbilic set of immersed surfaces in three-dimensional space forms },
  journal = { Bull. Sci. Math. },
  year = { 2020 },
  pages = {  },
  URL = { https://gecogedi.dimai.unifi.it/paper/459/ },
  note = { cvgmt preprint}
}