diff --git a/free-programming-books-ch.md b/free-programming-books-ch.md
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--- a/free-programming-books-ch.md
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@@ -1,6 +1,6 @@
 ###目录
 * [一些书目](#一些书目)
-* [GUI编程](#GUI编程)
+* [GUI编程](#gui编程)
 * [图形学相关](#图形学相关)
 * [语言无关类](#语言无关类)
     * [算法和数据结构](#算法和数据结构)