3Joe Klein,Why Barack Obama Is Winning,Time[EB/OL],http://www.time.com/time/politics/article/0,8599,1853025-4,00.html,2008-10-22. 被引量：1
4The White House Office of the Press Secretary,Remarks by the President in State of the Union Address[EB/OL],http://www.whitehouse.gov/the-press-office/remarks-president-state-union-address,2010-01-27. 被引量：1
