I think I read it on Sharp Charts in the chart school section. Something about if it closes three days in a row to look for a bounce to come. It holds pretty true to the rule, may only be a day or two then it might sell off more. I played UNG a while back (first of Sept.) and had some good luck doing so.
I have noticed that a couple other picks from this board are also closing this way, Candy & Nuts for Xmass if it plays out.