Xiaoqiang Zheng and Alex Pang.
  <b>Topological Lines in 3D Tensor Fields</b>.
  <i>IEEE Visualization</i>, 2004.
  <A HREF="http://vis.cs.brown.edu/docs/pdf/bib/g/Zheng-2004-TLT.pdf.html">(pdf)</A>
  <A HREF="http://vis.cs.brown.edu/results/bibtex/Zheng-2004-TLT.bib">(bibtex:
  Zheng-2004-TLT)</A>.<br />