To cite package ‘lookup’ in publications use:

  Hester J, Wickham H, Csárdi G (2024). _lookup: Lookup R function
  definitions, including compiled code, S3 and S4 methods_. R package
  version 0.0.0.9000, <https://github.com/jimhester/lookup>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {lookup: Lookup R function definitions, including compiled code, S3 and
S4 methods},
    author = {Jim Hester and Hadley Wickham and Gábor Csárdi},
    year = {2024},
    note = {R package version 0.0.0.9000},
    url = {https://github.com/jimhester/lookup},
  }