diff --git a/api-ref/src/docbkx/preface.xml b/api-ref/src/docbkx/preface.xml
index 758b77e04..9d08e18c5 100644
--- a/api-ref/src/docbkx/preface.xml
+++ b/api-ref/src/docbkx/preface.xml
@@ -60,6 +60,6 @@
To learn how to use the APIs, see the OpenStack + href="http://developer.openstack.org/api-guide/quick-start/">OpenStack API Guide and OpenStack API Complete Reference.
- +