@inproceedings{Engel:201643,
  author = "Engel, Ralph Richard",
  title = "{Upgrade of the Pierre Auger Observatory }",
  doi = "10.22323/1.236.0686",
  booktitle = "Proceedings of The 34th International Cosmic Ray Conference {\textemdash} PoS(ICRC2015)",
  year = 2016,
  volume = "236",
  pages = "686"
}