To cite package ‘haven’ in publications use:

  Wickham H, Miller E, Smith D (2023). _haven: Import and Export
  'SPSS', 'Stata' and 'SAS' Files_. R package version 2.5.4,
  <https://CRAN.R-project.org/package=haven>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {haven: Import and Export 'SPSS', 'Stata' and 'SAS' Files},
    author = {Hadley Wickham and Evan Miller and Danny Smith},
    year = {2023},
    note = {R package version 2.5.4},
    url = {https://CRAN.R-project.org/package=haven},
  }