Daniel Keefe.
  <i><b>Interactive 3D Drawing for Free-Form Modeling in
  Scientific Visualization and Art: Tools, Methodologies, and Theoretical
  Foundations</b></i>.
  PhD thesis, Brown University, 2007.
  <A HREF="http://vis.cs.brown.edu/docs/pdf/g/Keefe-2007-I3D.pdf.html">(pdf)</A>
  <A HREF="http://vis.cs.brown.edu/results/bibtex/Keefe-2007-I3D.bib">(bibtex:
  Keefe-2007-I3D)</A>.<br />