Zhizhou Wang, Baba C. Vemuri, Yunmei Chen, and Thomas H. Mareci.
  <b>A constrained variational principle for direct estimation and
  smoothing of the diffusion tensor field from complex DWI</b>.
  <i>IEEE Transactions on Medical Imaging</i>, 23(8):930-939, 2004.
  <A HREF="http://vis.cs.brown.edu/docs/pdf/bib/g/Wang-2004-CVP.pdf.html">(pdf)</A>
  <A HREF="http://vis.cs.brown.edu/results/bibtex/Wang-2004-CVP.bib">(bibtex:
  Wang-2004-CVP)</A>.<br />