http://blog.sina.com.cn/s/blog_bf1e123a0101e0h0.html
http://mt.sohu.com/20160802/n462208469.shtml
http://www.cnblogs.com/v-July-v/archive/2011/02/22/1983674.html
傅里叶
原文：http://www.cnblogs.com/liding/p/6360944.html
