@Misc{ 
  Lor13a,
  author = { Lorent, Andrew },
  title = { Rigidity of pairs of quasiregular mappings whose symmetric part of gradient are close },
  journal = {  },
  year = { 2013 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/2299/ },
  note = { cvgmt preprint}
}