@INPROCEEDINGS{Rebhan-ICANN-2007,
  author = {Rebhan, Sven and Eggert, Julian and Gross, Horst-Michael and Koerner,
    Edgar},
  title = {Sparse and Transformation-Invariant Hierarchical {NMF}},
  booktitle = {Artificial Neural Networks - ICANN 2007 (ICANN)},
  year = {2007},
  pages = {894--903},
  volume = {4668},
  number = {1},
  series = {LNCS},
  publisher = {Springer}
}