To cite package ‘round’ in publications use:

  Maechler M (2024). _round: Rounding to Decimal Digits_. R package
  version 0.21-0.2, <https://gitlab.com/mmaechler/round>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {round: Rounding to Decimal Digits},
    author = {Martin Maechler},
    year = {2024},
    note = {R package version 0.21-0.2},
    url = {https://gitlab.com/mmaechler/round},
  }