@Article{ 
  mag07a,
  author = { Magnani, Valentino },
  title = { Towards Differential Calculus in stratified groups  },
  journal = { J. Aust. Math. Soc. },
  year = { 2013 },
  volume = { 95 },
  number = { 1 },
  pages = { 76-128 },
  URL = { http://cvgmt.sns.it/paper/876/ },
  note = { cvgmt preprint}
}