@article{onlearningtheinvisibleinphotoacoustic,
  title = {On Learning the Invisible in Photoacoustic Tomography with Flat Directionally Sensitive Detector},
  author = {Bolin Pan and Marta M. Betcke},
  year = {2022},
  eprint = {2204.10001},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2204.10001v2},
}