@article{Bisnovatyi-Kogan:2020Dq,
  author = "Bisnovatyi-Kogan, Gennady  and  Tsupko, O. Yu.  and  Perlick, Volker",
  title = "{Shadow of a black hole at local and cosmological distances}",
  doi = "10.22323/1.362.0009",
  journal = "PoS",
  year = 2020,
  volume = "MULTIF2019",
  pages = "009"
}