@article{learningsparsecausalmodelsisnotnphard,
  title = {Learning Sparse Causal Models is not NP-hard},
  author = {Tom Claassen and Joris Mooij and Tom Heskes},
  year = {2013},
  eprint = {1309.6824},
  archivePrefix = {arXiv},
  url = {http://arxiv.org/abs/1309.6824v1},
}