diff --git a/readme.md b/readme.md
index f846de1..ca9696b 100644
--- a/readme.md
+++ b/readme.md
@@ -5,4 +5,15 @@ It seams that most other websocket implementations are using zlib for deflate.
 
 ### Refrences
 [Compression Extensions for WebSocket](https://datatracker.ietf.org/doc/html/rfc7692)  
-[zlib 1.2.13 Manual](https://www.zlib.net/manual.html)
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+[zlib 1.2.13 Manual](https://www.zlib.net/manual.html)
+
+
+### Notes
+
+get zlib source into zlib folder:
+```sh
+wget https://github.com/madler/zlib/releases/download/v1.2.13/zlib-1.2.13.tar.gz
+tar xvf zlib-1.2.13.tar.gz
+rm zlib-1.2.13.tar.gz
+mv zlib-1.2.13 zlib
+```
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