@Article{ 
  balrogzrc04,
  author = { Balogh, Zoltan and Rogovin, Kevin and Zürcher, Thomas },
  title = { The Stepanov differentiability theorem in metric measure spaces },
  journal = { Journal of Geometric Analysis },
  year = { 2004 },
  volume = { 14 },
  number = { 3 },
  pages = { 405-422 },
  URL = { http://cvgmt.sns.it/paper/522/ },
  note = { cvgmt preprint}
}