diff --git a/manual.md b/manual.md
index d4f6d22d..a2b72d83 100644
--- a/manual.md
+++ b/manual.md
@@ -71,13 +71,12 @@
 + [8.3. Vector types](#section8_3)
 + [8.4. Lighting](#section8_4)
 + [9. References](#section9)
-+ [9.1. GLM development](#section9_1)
-+ [9.2. OpenGL specifications](#section9_2)
-+ [9.3. External links](#section9_3)
-+ [9.4. Projects using GLM](#section9_4)
-+ [9.5. OpenGL tutorials using GLM](#section9_5)
-+ [9.6. Equivalent for other languages](#section9_6)
-+ [9.7. Alternatives to GLM](#section9_7)
++ [9.1. OpenGL specifications](#section9_1)
++ [9.2. External links](#section9_2)
++ [9.3. Projects using GLM](#section9_3)
++ [9.4. OpenGL tutorials using GLM](#section9_4)
++ [9.5. Equivalent for other languages](#section9_5)
++ [9.6. Alternatives to GLM](#section9_6)
 + [9.8. Acknowledgements](#section9_8)
 
 ---