To cite package ‘ggjoy’ in publications use:

  Wilke C (2018). _ggjoy: Joyplots in 'ggplot2'_. R package version
  0.4.1, <https://github.com/clauswilke/ggjoy>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {ggjoy: Joyplots in 'ggplot2'},
    author = {Claus O. Wilke},
    year = {2018},
    note = {R package version 0.4.1},
    url = {https://github.com/clauswilke/ggjoy},
  }