diff --git a/doc/manual/manual.xml b/doc/manual/manual.xml
index 84357e7fda..9ff13d9dfc 100644
--- a/doc/manual/manual.xml
+++ b/doc/manual/manual.xml
@@ -1,11 +1,8 @@
 <?xml version="1.0"?>
 <!DOCTYPE book
-    PUBLIC "-//OASIS//DTD DocBook EBNF Module V1.0//EN"
-    "http://www.oasis-open.org/docbook/xml/ebnf/1.0/dbebnf.dtd"
-[
-<!-- <!DOCTYPE book
     PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
-    "http://www.docbook.org/xml/4.3/docbook-xml-4.3.zip" -->
+    "http://www.docbook.org/xml/4.3/docbook-xml-4.3.zip"
+[
 <!ENTITY introduction SYSTEM "introduction.xml">
 <!ENTITY quick-start SYSTEM "quick-start.xml">
 <!ENTITY installation SYSTEM "installation.xml">
@@ -21,7 +18,7 @@
 <!ENTITY nix-push SYSTEM "nix-push.xml">
 <!ENTITY nix-pull SYSTEM "nix-pull.xml">
 <!ENTITY nix-prefetch-url SYSTEM "nix-prefetch-url.xml">
-<!ENTITY nix-lang-ref SYSTEM "nix-lang-ref.xml">
+<!-- <!ENTITY nix-lang-ref SYSTEM "nix-lang-ref.xml"> -->
 <!ENTITY troubleshooting SYSTEM "troubleshooting.xml">
 <!ENTITY bugs SYSTEM "bugs.xml">
 <!ENTITY version SYSTEM "version.xml">
@@ -82,7 +79,7 @@
     </sect1>
   </appendix>
 
-  &nix-lang-ref;
+<!--  &nix-lang-ref; -->
 
   &troubleshooting;
   &bugs;