@article{matroidshittingsetsandunsupervised,
  title = {Matroids Hitting Sets and Unsupervised Dependency Grammar Induction},
  author = {Nicholas Harvey and Vahab Mirrokni and David Karger and Virginia Savova and Leonid Peshkin},
  year = {2017},
  eprint = {1705.08992},
  archivePrefix = {arXiv},
  url = {http://arxiv.org/abs/1705.08992v2},
}