Gordon Kindlmann, David Weinstein, and David Hart.
  <b>Hue-Balls and Lit-Tensors for Direct Volume Rendering of
  Diffusion Tensor Fields</b>.
  <i>VIS '99: Proceedings of the conference on Visualization '99</i>,
  pages 183-189, 1999.
  <A HREF="http://vis.cs.brown.edu/docs/pdf/bib/g/Kindlmann-1999-HBL.pdf.html">(pdf)</A>
  <A HREF="http://vis.cs.brown.edu/results/bibtex/Kindlmann-1999-HBL.bib">(bibtex:
  Kindlmann-1999-HBL)</A>.<br />