See here. (Run it through Google translate if, like me, you don’t know any Russian.) I don’t know anything here, will defer to the experts on this one.
P.S. Tim Frye tells me that there was a sign at the demonstration over the weekend about Mr. Churov, the head of the State Electoral Commissions, “We don’t believe Churov, We believe Gauss.” I did a quick search and found this:
Tim also says there is a book by Mikhail Mygkov and Peter Ordeshook and one other person called Electoral Forensics which uses similar methods to analyze all russian elections, plus some in ukraine and even a couple of states in the US, e.g., florida in 2000, Ohio 2004.