diff --git a/doc/manual/installation.xml b/doc/manual/installation.xml
index b6cc6e7f9b..b9358efd1d 100644
--- a/doc/manual/installation.xml
+++ b/doc/manual/installation.xml
@@ -152,7 +152,7 @@ $ rm -rf /nix/var</screen>
 
 <para>You can install the latest stable version of Nix through Nix
 itself by subscribing to the channel <link
-xlink:href="http://nix.cs.uu.nl/dist/nix/channels-v3/nix-stable" /> ,
+xlink:href="http://nix.cs.uu.nl/dist/nix/channels-v3/nix-stable" />,
 or the latest unstable version by subscribing to the channel<link
 xlink:href="http://nix.cs.uu.nl/dist/nix/channels-v3/nix-unstable" />.
 You can also do a <link linkend="sec-one-click">one-click
diff --git a/doc/manual/nix-build.xml b/doc/manual/nix-build.xml
index bb64085f83..541275c523 100644
--- a/doc/manual/nix-build.xml
+++ b/doc/manual/nix-build.xml
@@ -9,7 +9,7 @@
 <refsynopsisdiv>
   <cmdsynopsis>
     <command>nix-build</command>
-    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="opt-common-syn.xml#xpointer(/nop/*)" />
+    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="opt-common-syn.xml#xmlns(db=http://docbook.org/ns/docbook)xpointer(/db:nop/*)" />
     <arg><option>--arg</option> <replaceable>name</replaceable> <replaceable>value</replaceable></arg>
     <arg>
       <group choice='req'>
diff --git a/doc/manual/nix-env.xml b/doc/manual/nix-env.xml
index 8669b9ccf6..247471d9bd 100644
--- a/doc/manual/nix-env.xml
+++ b/doc/manual/nix-env.xml
@@ -9,7 +9,7 @@
 <refsynopsisdiv>
   <cmdsynopsis>
     <command>nix-env</command>
-    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="opt-common-syn.xml#xpointer(/nop/*)" />
+    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="opt-common-syn.xml#xmlns(db=http://docbook.org/ns/docbook)xpointer(/db:nop/*)" />
     <arg><option>--arg</option> <replaceable>name</replaceable> <replaceable>value</replaceable></arg>
     <arg>
       <group choice='req'>
diff --git a/doc/manual/nix-instantiate.xml b/doc/manual/nix-instantiate.xml
index 71c8d3ec37..24d4c45d32 100644
--- a/doc/manual/nix-instantiate.xml
+++ b/doc/manual/nix-instantiate.xml
@@ -9,7 +9,7 @@
 <refsynopsisdiv>
   <cmdsynopsis>
     <command>nix-instantiate</command>
-    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="opt-common-syn.xml#xpointer(/nop/*)" />
+    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="opt-common-syn.xml#xmlns(db=http://docbook.org/ns/docbook)xpointer(/db:nop/*)" />
     <arg><option>--arg</option> <replaceable>name</replaceable> <replaceable>value</replaceable></arg>
     <arg>
       <group choice='req'>
diff --git a/doc/manual/nix-prefetch-url.xml b/doc/manual/nix-prefetch-url.xml
index a0d5a97f1f..b341fd88a8 100644
--- a/doc/manual/nix-prefetch-url.xml
+++ b/doc/manual/nix-prefetch-url.xml
@@ -1,4 +1,5 @@
-<refentry>
+<refentry xmlns="http://docbook.org/ns/docbook"
+          xmlns:xlink="http://www.w3.org/1999/xlink">
   
 <refnamediv>
   <refname>nix-prefetch-url</refname>
diff --git a/doc/manual/nix-store.xml b/doc/manual/nix-store.xml
index 5edc1cdaa2..038fd523f0 100644
--- a/doc/manual/nix-store.xml
+++ b/doc/manual/nix-store.xml
@@ -9,7 +9,7 @@
 <refsynopsisdiv>
   <cmdsynopsis>
     <command>nix-store</command>
-    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="opt-common-syn.xml#xpointer(/nop/*)" />
+    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="opt-common-syn.xml#xmlns(db=http://docbook.org/ns/docbook)xpointer(/db:nop/*)" />
     <arg><option>--add-root</option> <replaceable>path</replaceable></arg>
     <arg><option>--indirect</option></arg>
     <arg choice='plain'><replaceable>operation</replaceable></arg>
diff --git a/doc/manual/opt-common-syn.xml b/doc/manual/opt-common-syn.xml
index 2e02d0038b..9aaabb8e98 100644
--- a/doc/manual/opt-common-syn.xml
+++ b/doc/manual/opt-common-syn.xml
@@ -1,4 +1,4 @@
-<nop>
+<nop xmlns="http://docbook.org/ns/docbook">
   
 <arg><option>--help</option></arg>
 <arg><option>--version</option></arg>