written by Maria Smizanska, Julius Hrivnac and Richard Lednicky.
You may get this note as a LaTeX file with four Postscript pictures: bckksi.eps, bckla.eps, lambda.eps and polariz.eps. You may also get the note as a dvi or Postscript. And finaly, there is a HypertTexted version. The note exists also in a Spires database.