To cite package ‘corrgram’ in publications use:

  Wright K (2021). _corrgram: Plot a Correlogram_. R package version
  1.14, , <https://github.com/kwstat/corrgram>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {corrgram: Plot a Correlogram},
    author = {Kevin Wright},
    year = {2021},
    note = {R package version 1.14, 
},
    url = {https://github.com/kwstat/corrgram},
  }