diff --git a/doc/src/sgml/postgres.sgml b/doc/src/sgml/postgres.sgml
index 522316c28e1a5960a70c98ef3e79d5a386779a2d..b47bf529a2a4eeee415944251d6cb052f52a7f7d 100644
--- a/doc/src/sgml/postgres.sgml
+++ b/doc/src/sgml/postgres.sgml
@@ -270,6 +270,6 @@
 
  &biblio;
  <![%include-index;[&bookindex;]]>
- <![%include-xslt-index;[<index></index>]]>
+ <![%include-xslt-index;[<index id="bookindex"></index>]]>
 
 </book>