diff --git a/free-programming-books.md b/free-programming-books.md
index 2e21a36a1..c11a7e54f 100755
--- a/free-programming-books.md
+++ b/free-programming-books.md
@@ -72,7 +72,7 @@
     * [D3.js](#d3js)
     * [Dojo](#dojo)
     * [jQuery](#jquery)
-    * [Knockout.js](#knockout.js)
+    * [Knockout.js](#knockoutjs)
     * [Node.js](#nodejs)
 * [LaTeX](#latex)
 * [Linux](#linux)