1 https://blog.csdn.net/atpccb/article/details/29196607
2 https://blog.csdn.net/elpmis/article/details/4500917
3 http://blog.sina.com.cn/s/blog_e739607d0102wqjx.html
4 http://www.cnblogs.com/huxiao-tee/p/4657851.html
5 https://www.cnblogs.com/huxiao-tee/p/4660352.html