diff --git a/language/oop5/interfaces.xml b/language/oop5/interfaces.xml
index b946538a2d..f549fad07c 100644
--- a/language/oop5/interfaces.xml
+++ b/language/oop5/interfaces.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <!-- $Revision$ -->
- <sect1 xml:id="language.oop5.interfaces" xmlns="http://docbook.org/ns/docbook">
+ <sect1 xml:id="language.oop5.interfaces" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
   <title>Object Interfaces</title>
   <para>
    Object interfaces allow you to create code which specifies which methods a
@@ -16,6 +16,11 @@
    All methods declared in an interface must be public; this is the nature of an
    interface.
   </para>
+  <para>
+   Note that it is possible to declare a <link
+   linkend="language.oop5.decon.constructor">constructor</link> in an interface,
+   what can be useful in some contexts, e.g. for use by factories.
+  </para>
   <sect2 xml:id="language.oop5.interfaces.implements">
    <title><literal>implements</literal></title>
    <para>