To cite package ‘contrast’ in publications use:

  Kuhn M, Weston S, Wing J, Forester J, Thaler T (2022). _contrast: A
  Collection of Contrast Methods_. R package version 0.24.2,
  <https://github.com/alanocallaghan/contrast>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {contrast: A Collection of Contrast Methods},
    author = {Max Kuhn and Steve Weston and Jed Wing and James Forester and Thorn Thaler},
    year = {2022},
    note = {R package version 0.24.2},
    url = {https://github.com/alanocallaghan/contrast},
  }