To cite package ‘almanac’ in publications use:

  Vaughan D (2026). _almanac: Tools for Working with Recurrence Rules_.
  R package version 1.0.1,
  <https://CRAN.R-project.org/package=almanac>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {almanac: Tools for Working with Recurrence Rules},
    author = {Davis Vaughan},
    year = {2026},
    note = {R package version 1.0.1},
    url = {https://CRAN.R-project.org/package=almanac},
  }