@Article{ 
  Mor17,
  author = { Moreno, Giovanni },
  title = { An introduction to completely exceptional $2^{\textrm{nd}}$ order scalar  PDEs },
  journal = { Banach Centre Publications },
  year = { 2017 },
  pages = {  },
  URL = { https://gecogedi.dimai.unifi.it/paper/382/ },
  note = { cvgmt preprint}
}