diff --git a/reference/zip/ziparchive/open.xml b/reference/zip/ziparchive/open.xml
index 625112f81b..ac226ba205 100644
--- a/reference/zip/ziparchive/open.xml
+++ b/reference/zip/ziparchive/open.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <!-- $Revision$ -->
-<refentry xml:id="ziparchive.open" xmlns="http://docbook.org/ns/docbook">
+<refentry xml:id="ziparchive.open" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
  <refnamediv>
   <refname>ZipArchive::open</refname>
   <refpurpose>Open a ZIP file archive</refpurpose>
@@ -36,22 +36,22 @@
        <itemizedlist>
         <listitem>
          <para>
-          <constant>ZipArchive::OVERWRITE</constant>
+          <constant><link linkend="ziparchive.constants.overwrite">ZipArchive::OVERWRITE</link></constant>
          </para>
         </listitem>
         <listitem>
          <para>
-          <constant>ZipArchive::CREATE</constant>
+          <constant><link linkend="ziparchive.constants.create">ZipArchive::CREATE</link></constant>
          </para>
         </listitem>
         <listitem>
          <para>
-          <constant>ZipArchive::EXCL</constant>
+          <constant><link linkend="ziparchive.constants.excl">ZipArchive::EXCL</link></constant>
          </para>
         </listitem>
         <listitem>
          <para>
-          <constant>ZipArchive::CHECKCONS</constant>
+          <constant><link linkend="ziparchive.constants.checkcons">ZipArchive::CHECKCONS</link></constant>
          </para>
         </listitem>
        </itemizedlist>