A. Pfefferbaum and E.V. Sullivan.
  <b>Increased brain white matter diffusivity in normal adult
  aging: Relationship to anisotropy and partial voluming</b>.
  <i>Magn Reson Med</i>, 49(5):953-961, 2003.
  <A HREF="http://vis.cs.brown.edu/docs/pdf/bib/g/Pfefferbaum-2003-IBW.pdf.html">(pdf)</A>
  <A HREF="http://vis.cs.brown.edu/results/bibtex/Pfefferbaum-2003-IBW.bib">(bibtex: Pfefferbaum-2003-IBW)</A>.<br />