To cite package ‘Guerry’ in publications use:

  Friendly M, Dray S (2023). _Guerry: Maps, Data and Methods Related to
  Guerry (1833) "Moral Statistics of France"_. R package version 1.8.3,
  , <https://github.com/friendly/guerry>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {Guerry: Maps, Data and Methods Related to Guerry (1833) "Moral
Statistics of France"},
    author = {Michael Friendly and Stephane Dray},
    year = {2023},
    note = {R package version 1.8.3, 
},
    url = {https://github.com/friendly/guerry},
  }