Colin Ware.
  <b>Color sequences for univariate maps: theory, experiments and
  principles</b>.
  <i>IEEE Computer Graphics and Applications</i>, 8(5):41-49, September
  1988.
  <A HREF="http://vis.cs.brown.edu/docs/pdf/bib/g/Ware-1988-CSU.pdf.html">(pdf)</A>
  <A HREF="http://vis.cs.brown.edu/results/bibtex/Ware-1988-CSU.bib">(bibtex:
  Ware-1988-CSU)</A>.<br />