To cite package ‘using’ in publications use:

  North A, McBain M (2025). _using: Add version constraints to
  library() calls_. R package version 0.4.0,
  <https://github.com/anthonynorth/using>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {using: Add version constraints to library() calls},
    author = {Anthony North and Miles McBain},
    year = {2025},
    note = {R package version 0.4.0},
    url = {https://github.com/anthonynorth/using},
  }