@inproceedings{learningmultilevelsparserepresentations,
  title = {Learning Multi-level Sparse Representations},
  author = {Ferran Diego Andilla and Fred A. Hamprecht},
  year = {2013},
  booktitle = {NeurIPS 2013 12},
  url = {http://papers.nips.cc/paper/5076-learning-multi-level-sparse-representations},
}