diff --git a/docs/sus2018/README.md b/docs/sus2018/README.md
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--- a/docs/sus2018/README.md
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@@ -1,3 +1,5 @@
 # YC 创业课 2018 中文笔记
 
 > 来源：[Library | Startup School](https://www.startupschool.org/library)
+> 
+> 协议：[CC BY-NC-SA 4.0](http://creativecommons.org/licenses/by-nc-sa/4.0/)