@inproceedings{expanrlhierarchicalreinforcementlearning,
  title = {ExpanRL: Hierarchical Reinforcement Learning for Course Concept Expansion in MOOCs},
  author = {Jifan Yu and Chenyu Wang and Gan Luo and Lei Hou and Juanzi Li and Jie Tang and Minlie Huang and Zhiyuan Liu},
  year = {2020},
  booktitle = {Asian Chapter of the Association for Computational Linguistics 2020},
  url = {https://aclanthology.org/2020.aacl-main.77},
}