@Misc{ 
  BalFra11,
  author = { Baldi, Annalisa and Franchi, Bruno },
  title = { Maxwell's equations in anisotropic media and  Maxwell's equations in Carnot groups as variational limits },
  journal = {  },
  year = { 2011 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/1699/ },
  note = { cvgmt preprint}
}