To cite package ‘colorplane’ in publications use:

  Buchsbaum BR (2023). _colorplane: Basic S4 Classes and Methods for
  Mapping Between Numeric Values and Colors_. R package version 0.5.0,
  <https://github.com/bbuchsbaum/colorplane>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {colorplane: Basic S4 Classes and Methods for Mapping Between Numeric Values
and Colors},
    author = {Bradley R Buchsbaum},
    year = {2023},
    note = {R package version 0.5.0},
    url = {https://github.com/bbuchsbaum/colorplane},
  }