Ariel Gabizon Ran Raz Ronen Shaltiel Deterministic Extractors for Bit-Fixing Sources by Obtaining an Independent Seed. 394-403 2004 conf/focs/2004 FOCS http://csdl.computer.org/comp/proceedings/focs/2004/2228/00/22280394abs.htm db/conf/focs/focs2004.html#GabizonRS04