@article{phaseofnonlinearsystems,
  title = {Phase of Nonlinear Systems},
  author = {Chao Chen and Di Zhao and Wei Chen and Sei Zhen Khong and Li Qiu},
  year = {2020},
  eprint = {2012.00692},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2012.00692v2},
}