@article{gu2016incorporating,
  title={Incorporating copying mechanism in sequence-to-sequence learning},
  author={Jiatao Gu, Zhengdong Lu, Hang Li, Victor OK Li},
  journal={arXiv preprint arXiv:1603.06393},
  url={https://arxiv.org/abs/1603.06393},
  year={2016}
}