To cite Immutables in publications use:

  O'Neil S (2026). _Immutables: Fast and Functional Data Structures_.
  doi:10.5281/zenodo.19686096
  <https://doi.org/10.5281/zenodo.19686096>. R package version 1.0.1,
  <https://oneilsh.github.io/immutables/>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {Immutables: Fast and Functional Data Structures},
    author = {Shawn T. O'Neil},
    year = {2026},
    note = {R package version 1.0.1},
    doi = {10.5281/zenodo.19686096},
    url = {https://oneilsh.github.io/immutables/},
  }