diff --git a/src/doc/hera-reference.xml b/src/doc/hera-reference.xml
index fa7de77..2218341 100644
--- a/src/doc/hera-reference.xml
+++ b/src/doc/hera-reference.xml
@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" 
-  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
+<!DOCTYPE book  [
   <!ENTITY core SYSTEM "../../hera-core/src/doc/core.xml">
   <!ENTITY metadata SYSTEM "../../hera-metadata/src/doc/metadata.xml">
 ]>
-<!-- book  -->
+<!-- PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" 
+  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" -->
 <book>
   <bookinfo>
     <title>Hera</title>
@@ -127,7 +127,6 @@
   </preface>
 
   &core;
-
   &metadata;
 
   <glossary>