To cite package ‘packrat’ in publications use:

  Atkins A, Allen T, Ushey K, McPherson J, Cheng J, Allaire J (2024).
  _packrat: A Dependency Management System for Projects and their R
  Package Dependencies_. R package version 0.9.2.9000,
  <https://github.com/rstudio/packrat>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {packrat: A Dependency Management System for Projects and their R Package
Dependencies},
    author = {Aron Atkins and Toph Allen and Kevin Ushey and Jonathan McPherson and Joe Cheng and JJ Allaire},
    year = {2024},
    note = {R package version 0.9.2.9000},
    url = {https://github.com/rstudio/packrat},
  }