@article{hierarchicallyfairfederatedlearning,
  title = {Hierarchically Fair Federated Learning},
  author = {Jingfeng Zhang and Cheng Li and Antonio Robles-Kelly and Mohan Kankanhalli},
  year = {2020},
  eprint = {2004.10386},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2004.10386v2},
}