1，https://www.zhihu.com/search?type=content&q=%E6%96%87%E4%BB%B6%E7%BC%93%E5%86%B2%E5%8C%BA

2，https://blog.csdn.net/socho/article/details/51842943?utm_source=blogxgwz9

3，https://blog.csdn.net/weixin_30919571/article/details/94796714?utm_medium=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-1.control&depth_1-utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-1.control