傅里叶变换

http://vdisk.weibo.com/s/aW42jaPITUNHa

http://www.docin.com/p-657665236.html

https://www.zhihu.com/question/22202980/answer/20973635

http://blog.csdn.net/baimafujinji/article/details/10931621


正态分布

https://cos.name/2013/01/story-of-normal-distribution-1/


复变函数与积分变换

https://wenku.baidu.com/view/3cc3cfc2aef8941ea66e0505.html


协方差矩阵

http://www.cnblogs.com/nsnow/p/4758202.html