To cite package ‘crosswordio’ in publications use:

  Cheng M (2025). _crosswordio: Read/Write Crosswords in PUZ Format_. R
  package version 0.1.0,
  <https://github.com/coolbutuseless/crosswordio>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {crosswordio: Read/Write Crosswords in PUZ Format},
    author = {Mike Cheng},
    year = {2025},
    note = {R package version 0.1.0},
    url = {https://github.com/coolbutuseless/crosswordio},
  }