To cite package ‘Apollonius’ in publications use:

  Laurent S (2023). _Apollonius: 2D Apollonius Graphs_. R package
  version 1.0.1, <https://CRAN.R-project.org/package=Apollonius>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {Apollonius: 2D Apollonius Graphs},
    author = {Stéphane Laurent},
    year = {2023},
    note = {R package version 1.0.1},
    url = {https://CRAN.R-project.org/package=Apollonius},
  }