diff --git a/chapter/ntp.tex b/chapter/ntp.tex
new file mode 100644
index 0000000..b4201e7
--- /dev/null
+++ b/chapter/ntp.tex
@@ -0,0 +1,7 @@
+\chapter{Network Time Protocol}
+
+\section{The old NTP from \tsq{85}
+
+\newpage
+
+\section{Secure NTP}
diff --git a/main.tex b/main.tex
index 93ac185..97c7ee6 100644
--- a/main.tex
+++ b/main.tex
@@ -33,9 +33,7 @@
 
 \include{chapter/internet}
 
-\import{chapter/}{management}
-
-\include{chapter/aaa}
+\include{chapter/management}
 
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