To cite cldreducer in publications, use:

  Ennis J (2026). _cldreducer: Reduce Compact Letter Displays_. R
  package version 0.3.5, <https://github.com/aigorahub/cld-reducer>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {{cldreducer}: Reduce Compact Letter Displays},
    author = {John Ennis},
    year = {2026},
    note = {R package version 0.3.5},
    url = {https://github.com/aigorahub/cld-reducer},
  }

The optional CLD-sigma method solves the assignment-minimum clique
covering problem of:

  Ennis JM, Fayle CM, Ennis DM (2012). “Assignment-Minimum Clique
  Coverings.” _ACM Journal of Experimental Algorithmics_, *17*.
  doi:10.1145/2133803.2275596
  <https://doi.org/10.1145/2133803.2275596>. Article 1.5.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {Assignment-Minimum Clique Coverings},
    author = {John M. Ennis and Charles M. Fayle and Daniel M. Ennis},
    journal = {ACM Journal of Experimental Algorithmics},
    volume = {17},
    note = {Article 1.5},
    year = {2012},
    doi = {10.1145/2133803.2275596},
  }