@article{hierarchicalcognitivespectrumsharingin,
  title = {Hierarchical Cognitive Spectrum Sharing in Space-Air-Ground Integrated Networks},
  author = {Zizhen Zhou and Qianqian Zhang and Jungang Ge and Ying-Chang Liang},
  year = {2023},
  eprint = {2312.08097},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2312.08097v1},
}