To cite package ‘vcdExtra’ in publications use:

Friendly M, Klorfine G (2026). vcdExtra: 'vcd' Extensions and Additions. R package version 0.9.6, https://github.com/friendly/vcdextra.

Corresponding BibTeX entry:

  @Manual{,
    title = {vcdExtra: 'vcd' Extensions and Additions},
    author = {Michael Friendly and Gavin Klorfine},
    year = {2026},
    note = {R package version 0.9.6},
    url = {https://github.com/friendly/vcdextra},
  }