@article{um4unifiedmultilingualmultipleteacher,
  title = {UM4: Unified Multilingual Multiple Teacher-Student Model for Zero-Resource Neural Machine Translation},
  author = {Jian Yang and Yuwei Yin and Shuming Ma and Dongdong Zhang and Shuangzhi Wu and Hongcheng Guo and Zhoujun Li and Furu Wei},
  year = {2022},
  eprint = {2207.04900},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2207.04900v2},
}