To cite ggtukey in publications, please use:

  Bass, E. (2023). ggtukey: Compact Letter Displays for 'ggplot2'
  (version 0.4.0).

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {ggtukey: Compact Letter Displays for 'ggplot2'},
    author = {Ethan Bass},
    year = {2023},
    note = {version 0.4.0},
    url = {https://ethanbass.github.io/ggtukey/},
  }