To cite package ‘Rfractran’ in publications use:

Witthoft C (2023). Rfractran: A 'FRACTRAN' Interpreter and Some Helper Functions. R package version 1.0.1, https://CRAN.R-project.org/package=Rfractran.

Corresponding BibTeX entry:

  @Manual{,
    title = {Rfractran: A 'FRACTRAN' Interpreter and Some Helper
      Functions},
    author = {Carl Witthoft},
    year = {2023},
    note = {R package version 1.0.1},
    url = {https://CRAN.R-project.org/package=Rfractran},
  }