@inproceedings{unambiguityregularizationforunsupervised,
  title = {Unambiguity Regularization for Unsupervised Learning of Probabilistic Grammars},
  author = {Kewei Tu and Vasant Honavar},
  year = {2012},
  booktitle = {EMNLP 2012 7},
  url = {https://aclanthology.org/D12-1121},
}