Reports fuel doubts on documents used in CBS News story on Bush's National Guard Service

Reports fuel doubts on documents used in CBS News story on Bush's National Guard Service: "Knox told the newspaper she did not recall typing the memos, but that they echoed Killian's views on Bush. She said he retained memos for a personal 'cover his back' file he kept in a locked drawer of his desk, but she was not sure what happened to them when he died in 1984. "