@inproceedings{Ulrich:2016oO,
  author = "Ulrich, Ralf Matthias",
  title = "{Extension of the measurement of the proton-air cross section with the Pierre Auger Observatory }",
  doi = "10.22323/1.236.0401",
  booktitle = "Proceedings of The 34th International Cosmic Ray Conference {\textemdash} PoS(ICRC2015)",
  year = 2016,
  volume = "236",
  pages = "401"
}