To cite package ‘proton’ in publications use:

  Biecek P (2015). _proton: The Proton Game_. R package version 1.0,
  <https://CRAN.R-project.org/package=proton>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {proton: The Proton Game},
    author = {Przemysław Biecek},
    year = {2015},
    note = {R package version 1.0},
    url = {https://CRAN.R-project.org/package=proton},
  }