To cite Polychrome in publications use:

Coombes KR, Brock G, Abrams ZB, Abruzzo LV (2019). “Polychrome: Creating and Assessing Qualitative Palettes with Many Colors.” Journal of Statistical Software, Code Snippets, 90(1), 1–23. doi:10.18637/jss.v090.c01.

Corresponding BibTeX entry:

  @Article{,
    title = {{Polychrome}: Creating and Assessing Qualitative Palettes
      with Many Colors},
    author = {Kevin R. Coombes and Guy Brock and Zachary B. Abrams and
      Lynne V. Abruzzo},
    journal = {Journal of Statistical Software, Code Snippets},
    year = {2019},
    volume = {90},
    number = {1},
    pages = {1--23},
    doi = {10.18637/jss.v090.c01},
  }