@article{1568598,
  author = {et M. Johnson al.},
  title = {Universal interferometric signatures of a black hole{\textquoteright}s photon ring},
  year = {2020},
  journal = {Science Advances},
  volume = {6},
  pages = {eaaz1310},
  url = {https://ui.adsabs.harvard.edu/abs/2020SciA....6.1310J/abstract},
  language = {eng},
}