To cite package ‘projr’ in publications use:

  Sumner M (2026). _projr: Comprehensive Interface to the PROJ
  Library_. R package version 0.0.1,
  <https://github.com/hypertidy/projr>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {projr: Comprehensive Interface to the PROJ Library},
    author = {Michael Sumner},
    year = {2026},
    note = {R package version 0.0.1},
    url = {https://github.com/hypertidy/projr},
  }