San Francisco Chronicle, May 4, 2010 by Jaxon Van Derbeken
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2010/05/04/MNJ71CTL6A.DTL
Clifford Gardner, an adjunct faculty member of UC Berkeley’s Boalt Hall law school who specializes in appeals, said courts have been receptive to overturning convictions under a 1963 U.S. Supreme Court decision involving disclosure of witnesses’ pasts, Brady vs. Maryland. “If the witness is important and the evidence impeaches the witness,” Gardner said, “Brady usually is going to require reversal.”