To cite package ‘lambda’ in publications use:

  Hester J (2024). _lambda: Simple anonymous functions_. R package
  version 0.0.0.9000, <https://github.com/jimhester/lambda>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {lambda: Simple anonymous functions},
    author = {Jim Hester},
    year = {2024},
    note = {R package version 0.0.0.9000},
    url = {https://github.com/jimhester/lambda},
  }