Horst Hahn and Heintz-Otto Peitgen.
  <b>IWT&mdash;Interactive Watershed Transform: A hierarchical method
  for efficient interactive and automated segmentation of multidimensional
  grayscale images</b>.
  <i>Proc. Medical Imaging,</i>, Feb 2003.
  <A HREF="http://vis.cs.brown.edu/docs/pdf/bib/g/Hahn-2003-IWT.pdf.html">(pdf)</A>
  <A HREF="http://vis.cs.brown.edu/results/bibtex/Hahn-2003-IWT.bib">(bibtex:
  Hahn-2003-IWT)</A>.<br />