David M. Weinstein, Gordon L. Kindlmann, and Eric C. Lundberg.
  <b>Tensorlines: Advection-diffusion based propagation through
  diffusion tensor fields.</b>
  In <i>IEEE Visualization '99</i>, pages 249-254, 1999.
  <A HREF="http://vis.cs.brown.edu/results/bibtex/Weinstein-1999-TAD.bib">(bibtex:
  Weinstein-1999-TAD)</A>.<br />