@article{covarianceestimationformatrixvalueddata,
  title = {Covariance Estimation for Matrix-valued Data},
  author = {Yichi Zhang and Weining Shen and Dehan Kong},
  year = {2020},
  eprint = {2004.05281},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2004.05281v2},
}