diff --git a/chapters/01_who_is_reading.md b/chapters/01_who_is_reading.md
index 693aee2..8f0c7fc 100644
--- a/chapters/01_who_is_reading.md
+++ b/chapters/01_who_is_reading.md
@@ -48,6 +48,10 @@ This tentacular surface reaches different moments in the life of a programmer: f
 -   different documentations for different readers
 -   wrap up
 
+```
+note: below are materials from previous writings
+```
+
 ### previous writings
 
 -   lowering barriers and creating entry points