@Article{ 
  AlGuMaMo17,
  author = { Dmitri V. Alekseevsky,  and Gutt, Jan and Manno, Gianni and Moreno, Giovanni },
  title = { Lowest degree invariant 2nd order PDEs over rational homogeneous contact
  manifolds },
  journal = { Communications in Contemporary Mathematics },
  year = { 2019 },
  pages = {  },
  URL = { https://gecogedi.dimai.unifi.it/paper/260/ },
  note = { cvgmt preprint}
}