diff --git a/features/gc.xml b/features/gc.xml
index 77fd8c0b03..efad31292f 100644
--- a/features/gc.xml
+++ b/features/gc.xml
@@ -1,12 +1,12 @@
 <?xml version="1.0" encoding="utf-8"?>
 <!-- $Revision$ -->
- <chapter xml:id="features.gc" xmlns="http://docbook.org/ns/docbook">
+ <chapter xml:id="features.gc" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>Garbage Collection</title>
 
   <para>
    This section explains the merits of the new Garbage Collection (also known
    as GC) mechanism that is part of PHP 5.3. This was originally written as a
-   three part column for <link xlink='&url.phparchitect;'>php|architect</link>.
+   three part column for <link xlink:href='&url.phparchitect;'>php|architect</link>.
   </para>
 
   <sect1 xml:id="features.gc.refcounting-basics">
@@ -40,7 +40,7 @@ $a = "new string";
     user-land reference has been created. The "refcount" is set to "1" as
     there is only one symbol that makes use of this variable container. Note
     that if "refcount" is "1", "is_ref" is always "false". If you have <link
-    xlink='&url.xdebug;'>Xdebug</link> installed, you can display this
+    xlink:href='&url.xdebug;'>Xdebug</link> installed, you can display this
     information by calling:
    </para>
    <para>
@@ -301,7 +301,7 @@ a: (refcount=2, is_ref=1)=array (
     Traditionally, reference counting memory mechanisms, such as that used by
     PHP, fail to address those circular reference memory leaks. Back in 2007,
     while looking into this issue, I was pointed to a paper by David F. Bacon
-    and V.T. Rajan titled "<link xlink='&url.gc-paper;'>Concurrent Cycle
+    and V.T. Rajan titled "<link xlink:href='&url.gc-paper;'>Concurrent Cycle
     Collection in Reference Counted Systems</link>". Although the paper was
     written with Java in mind, I started to play around with it to see if it
     was feasible to implement the synchronous algorithm, as outlined in the
diff --git a/reference/nis/configure.xml b/reference/nis/configure.xml
index b718c16c94..e3499ad553 100644
--- a/reference/nis/configure.xml
+++ b/reference/nis/configure.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
 <!-- $Revision$ -->
-<section xml:id="nis.installation" xmlns="http://docbook.org/ns/docbook">
+<section xml:id="nis.installation" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
  &reftitle.install;
  <para>
   &pecl.info;