To cite colorspace in publications use

Ross Ihaka, Paul Murrell, Kurt Hornik, Achim Zeileis (2012). colorspace: Color Space Manipulation. R package version 1.1-1. URL http://CRAN.R-project.org/package=colorspace

If you use HCL-based color palettes, please cite:

Achim Zeileis, Kurt Hornik, Paul Murrell (2009). Escaping RGBland: Selecting Colors for Statistical Graphics. Computational Statistics & Data Analysis, 53, 3259-3270. doi:10.1016/j.csda.2008.11.033

Corresponding BibTeX entries:

  @Manual{,
    title = {{colorspace}: Color Space Manipulation},
    author = {Ross Ihaka and Paul Murrell and Kurt Hornik and Achim
      Zeileis},
    year = {2012},
    note = {R package version 1.1-1},
    url = {http://CRAN.R-project.org/package=colorspace},
  }

  @Article{,
    title = {Escaping {RGB}land: Selecting Colors for Statistical
      Graphics},
    author = {Achim Zeileis and Kurt Hornik and Paul Murrell},
    journal = {Computational Statistics \& Data Analysis},
    year = {2009},
    volume = {53},
    pages = {3259--3270},
    doi = {10.1016/j.csda.2008.11.033},
  }