To cite package ‘plot.matrix’ in publications use:

  Klinke S (2022). _plot.matrix: Visualizes a Matrix as Heatmap_. R
  package version 1.6.2,
  <https://github.com/sigbertklinke/plot.matrix>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {plot.matrix: Visualizes a Matrix as Heatmap},
    author = {Sigbert Klinke},
    year = {2022},
    note = {R package version 1.6.2},
    url = {https://github.com/sigbertklinke/plot.matrix},
  }