@Article{ 
  San16a,
  author = { Santi, Andrea },
  title = { A generalized integrability problem for G-Structures },
  journal = { Ann. Mat. Pura Appl. },
  year = { 2016 },
  doi = { 10.1007/s10231-015-0523-x },
  volume = { 195 },
  number = { 5 },
  pages = { 1463-1489 },
  URL = { https://gecogedi.dimai.unifi.it/paper/31/ },
  note = { cvgmt preprint}
}