To cite package ‘ggCheysson’ in publications use:

  Friendly M (2026). _ggCheysson: Graphic Styles of Emile Cheysson for
  'ggplot2'_. R package version 1.0.0,
  <https://github.com/friendly/ggcheysson>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {ggCheysson: Graphic Styles of Emile Cheysson for 'ggplot2'},
    author = {Michael Friendly},
    year = {2026},
    note = {R package version 1.0.0},
    url = {https://github.com/friendly/ggcheysson},
  }