@inproceedings{openhierarchicalrelationextraction,
  title = {Open Hierarchical Relation Extraction},
  author = {Kai Zhang and Yuan YAO and Ruobing Xie and Xu Han and Zhiyuan Liu and Fen Lin and Leyu Lin and Maosong Sun},
  year = {2021},
  booktitle = {NAACL 2021 4},
  url = {https://aclanthology.org/2021.naacl-main.452},
}