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http://www.cnblogs.com/devinzhang/archive/2012/02/28/2371631.html
http://www.cnblogs.com/montaque/archive/2005/05/17/157095.html
http://www.cnblogs.com/tuyile006/archive/2011/02/22/1961679.html
http://www.cnblogs.com/zhuqil/archive/2012/07/23/2604572.html
http://www.cnblogs.com/adforce/archive/2012/11/27/2790937.html