Luis M. Portela.
  <i><b>Identification and Characterization of Vortices in the
  Turbulent Boundary Layer. Volume I</b></i>.
  PhD thesis, Stanford University, November 1997.
  <A HREF="http://vis.cs.brown.edu/docs/pdf/bib/g/Portela-1997-ICV.pdf.html">(pdf)</A>
  <A HREF="http://vis.cs.brown.edu/results/bibtex/Portela-1997-ICV.bib">(bibtex:
  Portela-1997-ICV)</A>.<br />