diff --git a/doc/developer_guide/developer_guide.md b/doc/developer_guide/developer_guide.md
index 2b78e0fc..db3f3359 100644
--- a/doc/developer_guide/developer_guide.md
+++ b/doc/developer_guide/developer_guide.md
@@ -50,6 +50,6 @@ Script `start-test-release-build` requires environment variable `GH_TOKEN` to co
 3. [Testing](testing.md)
 4. [Running tests in the CI](ci.md)
 5. [Updating Packages](updating_packages.md)
-6[Notebooks](notebooks.md)
+6. [Notebooks](notebooks.md)