@inproceedings{onalgorithmsforsparsemultifactornmf,
  title = {On Algorithms for Sparse Multi-factor NMF},
  author = {Siwei Lyu and Xin Wang},
  year = {2013},
  booktitle = {NeurIPS 2013 12},
  url = {http://papers.nips.cc/paper/5141-on-algorithms-for-sparse-multi-factor-nmf},
}