@Article{ 
  Alt14,
  author = { Altavilla, Amedeo },
  title = { On the real differential of a slice regular function },
  journal = { Advances in Geometry },
  year = { 2018 },
  doi = { https://doi.org/10.1515/advgeom-2017-0044 },
  volume = { 18 },
  number = { 1 },
  pages = { 5--26 },
  URL = { https://gecogedi.dimai.unifi.it/paper/92/ },
  note = { cvgmt preprint}
}