Willis D. Ellis.
  <i><b>A source book of gestalt psychology</b></i>.
  Harcourt, Brace, and company, New York, NY, 1939.
  <A HREF="http://vis.cs.brown.edu/results/bibtex/Ellis-1939-SBG.bib">(bibtex:
  Ellis-1939-SBG)</A>.<br />