http://www.taikr.com/course/448/tasks
http://www.xuanyusong.com/archives/1840
http://www.cnblogs.com/qiaogaojian/p/5920998.html
http://blog.csdn.net/u014725878/article/details/51481259
http://blog.csdn.net/zzmkljd/article/details/53409173
http://www.taikr.com/article/2747
http://bbs.9ria.com/thread-406364-1-1.html