FILE - This combo image shows NFL Players' lawyer David Frederick, left, in a November 2008 file photo, and NFL lawyer Paul Clement in a June 2011 file photo. With perhaps billions of dollars stake,

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FILE - This combo image shows NFL Players' lawyer David Frederick, left, in a November 2008 file photo, and NFL lawyer Paul Clement in a June 2011 file photo. With perhaps billions of dollars stake, a hearing Tuesday, April 8, 2013 over concussion litigation filed against the NFL promises to be a brawl between the legal heavyweights. (AP Photo/File) less 

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Associated Press
Mon, Apr 8, 2013 9:30 PM EDT