@Article{ 
  SteTre21,
  author = { Stepanov, Eugene and Trevisan, Dario },
  title = { On exterior differential systems involving differentials of H\"{o}lder functions },
  journal = { J. Differential Equations },
  year = { 2022 },
  doi = { https://doi.org/10.1016/j.jde.2022.07.037 },
  volume = { 337 },
  pages = { 91–137 },
  URL = { http://cvgmt.sns.it/paper/5374/ },
  note = { cvgmt preprint}
}