http://www.cnblogs.com/TianFang/archive/2008/09/15/1291050.html
http://www.cnblogs.com/TianFang/archive/2008/09/19/1294521.html
http://www.cnblogs.com/TianFang/archive/2008/09/20/1294590.html
原文：http://www.cnblogs.com/justme-cloud-coder/p/4455692.html