To cite package ‘iso8601’ in publications use:

  van der Laan J (2024). _iso8601: Working with ISO8601 Dates and
  Times_. R package version 0.1.2,
  <https://CRAN.R-project.org/package=iso8601>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {iso8601: Working with ISO8601 Dates and Times},
    author = {Jan {van der Laan}},
    year = {2024},
    note = {R package version 0.1.2},
    url = {https://CRAN.R-project.org/package=iso8601},
  }