@inproceedings{Hnatyk:2021Lb,
  author = "Hnatyk, Roman  and  Voitsekhovskyi, Vadym",
  title = "{Extremely high energy (E > 10^{20} eV) cosmic rays: observations and potential sources}",
  doi = "10.22323/1.395.0464",
  booktitle = "Proceedings of 37th International Cosmic Ray Conference {\textemdash} PoS(ICRC2021)",
  year = 2021,
  volume = "395",
  pages = "464"
}