@inproceedings{heesch-02a,
   author = {D Heesch and S R\"{u}ger},
   title = "Combining Features for content-based sketch retrieval --- a comparative evaluation of retrieval performance",
   booktitle = "Proc Europ Colloquium Information Retrieval Research",
   publisher = "LNCS 2291, Springer",
   pages = "41--52",
   year = "2002"
  }