diff --git a/docbook/docbook-xml/docbook.dtd b/docbook/docbook-xml/docbook.dtd
index ba33b842d..e7e60896c 100644
--- a/docbook/docbook-xml/docbook.dtd
+++ b/docbook/docbook-xml/docbook.dtd
@@ -25,7 +25,6 @@
 	linkend	IDREF	#IMPLIED
 	xmlns:xlink	CDATA	#FIXED	'http://www.w3.org/1999/xlink'
 	xmlns:xi	CDATA	#FIXED	'http://www.w3.org/2001/XInclude'
-	xmlns:phpdoc CDATA  #FIXED  'http://php.net/ns/phpdoc'
 	xlink:href	CDATA	#IMPLIED
 	xlink:type	CDATA	#IMPLIED
 	xlink:role	CDATA	#IMPLIED
@@ -2532,7 +2531,7 @@
 
 >
 
-<!ELEMENT book (((title|titleabbrev|subtitle)*, info?), (glossary|bibliography|index|toc|dedication|acknowledgements|preface|chapter|appendix|article|colophon|part|reference|phpdoc:exceptionref|phpdoc:classref)+)>
+<!ELEMENT book (((title|titleabbrev|subtitle)*, info?), (glossary|bibliography|index|toc|dedication|acknowledgements|preface|chapter|appendix|article|colophon|part|reference)+)>
 
 <!ATTLIST book
 	xmlns	CDATA	#FIXED	"http://docbook.org/ns/docbook"
@@ -2604,7 +2603,7 @@
 
 >
 
-<!ELEMENT part (((title|titleabbrev|subtitle)*, info?), partintro?, (glossary|bibliography|index|toc|dedication|acknowledgements|preface|chapter|appendix|article|colophon|refentry|reference|phpdoc:exceptionref|phpdoc:classref)+)>
+<!ELEMENT part (((title|titleabbrev|subtitle)*, info?), partintro?, (glossary|bibliography|index|toc|dedication|acknowledgements|preface|chapter|appendix|article|colophon|refentry|reference)+)>
 
 <!ATTLIST part
 	xmlns	CDATA	#FIXED	"http://docbook.org/ns/docbook"