@misc{protheroe1998acceleration,
  title={Acceleration and Interaction of Ultra High Energy Cosmic Rays},
  author={R. J. Protheroe},
  year={1998},
  eprint={astro-ph/9812055},
  archivePrefix={arXiv},
  primaryClass={astro-ph},
  url={https://arxiv.org/abs/astro-ph/9812055}
}