@Misc{ 
  ambkir99,
  author = { Ambrosio, Luigi and Kirchheim, Bernd },
  title = { Rectifiable Sets in Metric and Banach Spaces },
  journal = { Submitted to Math. Annalen.  },
  year = { 1999 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/1513/ },
  note = { cvgmt preprint}
}