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WikiPedia: Đỗ_Việt_Khoa http://vnexpress.net/GL/Xa-hoi/2008/11/3BA0899D/ http://vnexpress.net/GL/Xa-hoi/Giao-duc/2006/07/3B... http://vnexpress.net/gl/xa-hoi/giao-duc/2012/06/ne... http://www.vnexpress.net/GL/Topic/?ID=3897 http://www.vnexpress.net/GL/Xa-hoi/2006/06/3B9EB25... http://www.vnexpress.net/GL/Xa-hoi/2008/11/3BA0878... http://www.vnexpress.net/GL/Xa-hoi/2008/11/3BA0899... http://www.vnexpress.net/GL/Xa-hoi/Giao-duc/2006/0... http://www.bbc.co.uk/vietnamese/vietnam/2010/05/10... http://dantri.com.vn/c25/s25-120900/giam-thi-to-ca...