To cite package ‘sets’ in publications use:

  Meyer D, Hornik K (2023). _sets: Sets, Generalized Sets, Customizable
  Sets and Intervals_. R package version 1.0-25,
  <https://CRAN.R-project.org/package=sets>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {sets: Sets, Generalized Sets, Customizable Sets and Intervals},
    author = {David Meyer and Kurt Hornik},
    year = {2023},
    note = {R package version 1.0-25},
    url = {https://CRAN.R-project.org/package=sets},
  }

  Meyer D, Hornik K (2009). “Generalized and Customizable Sets in R.”
  _Journal of Statistical Software_, *31*(2), 1-27.
  doi:10.18637/jss.v031.i02 <https://doi.org/10.18637/jss.v031.i02>.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {Generalized and Customizable Sets in {R}},
    author = {David Meyer and Kurt Hornik},
    journal = {Journal of Statistical Software},
    year = {2009},
    volume = {31},
    number = {2},
    pages = {1--27},
    doi = {10.18637/jss.v031.i02},
  }