http://www.cnblogs.com/mybkn/archive/2012/05/18/2508306.html
http://www.cnblogs.com/haippy/archive/2012/05/20/2509329.html
http://www.cnblogs.com/cyjch/archive/2012/02/15/2352792.html
http://www.2cto.com/kf/201110/109535.html
原文:http://www.cnblogs.com/youxin/p/3972041.html