To cite package ‘Gifi’ in publications use:

  Mair P, De Leeuw J (2022). _Gifi: Multivariate Analysis with Optimal
  Scaling_. R package version 0.4-0,
  <https://r-forge.r-project.org/projects/psychor>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {Gifi: Multivariate Analysis with Optimal Scaling},
    author = {Patrick Mair and Jan {De Leeuw}},
    year = {2022},
    note = {R package version 0.4-0},
    url = {https://r-forge.r-project.org/projects/psychor},
  }