@inproceedings{ptbgraphparsingwithtreeapproximation,
  title = {PTB Graph Parsing with Tree Approximation},
  author = {Yoshihide Kato and Shigeki Matsubara},
  year = {2019},
  booktitle = {ACL 2019 7},
  url = {https://aclanthology.org/P19-1530},
}