diff --git a/default.docbook b/default.docbook
index 66dfbef8d..e1c8e0134 100644
--- a/default.docbook
+++ b/default.docbook
@@ -1,6 +1,11 @@
 <?xml version="1.0" encoding="utf-8" ?>
+$if(mathml)$
+<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook EBNF Module V1.1CR1//EN"
+                  "http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd">
+$else$
 <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
                   "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd">
+$endif$
 <article>
   <articleinfo>
     <title>$title$</title>