E.O. Stejskal and J.E. Tanner.
  <b>Spin diffusion measurements: spin echoes in the </b>.
  <i>J. Chem. Phys.</i>, 42:288-292, 1965.
  <A HREF="http://vis.cs.brown.edu/docs/pdf/bib/g/Stejskal-1965-SDM.pdf.html">(pdf)</A> <A HREF="http://vis.cs.brown.edu/results/bibtex/Stejskal-1965-SDM.bib">(bibtex:
  Stejskal-1965-SDM)</A>.<br />