title: External referenced DTD in XML
body: <p>test.xml:</p>
  
  <pre><code>&lt;?xml version='1.0' encoding='UTF-8'?&gt;
  &lt;!DOCTYPE email SYSTEM "test.dtd"&gt;
  &lt;email&gt;
  &lt;von&gt;test@test.com&lt;/von&gt;
  &lt;zu&gt;xxx@example.com&lt;/zu&gt;
  &lt;titel&gt;Hello&lt;/titel&gt;
  &lt;text&gt;Dear John....;-).&lt;/text&gt;
  &lt;prior type="schnell"/&gt;
  &lt;/email&gt;
  </code></pre>
  
  <p>test.dtd:</p>
  
  <pre><code>&lt;?xml version='1.0' encoding='UTF-8'?&gt;
  &lt;!DOCTYPE email [
  &lt;!ELEMENT email (von,zu,titel,text,prior)&gt;
  &lt;!ELEMENT von (#PCDATA)&gt;
  &lt;!ELEMENT zu (#PCDATA)&gt;
  &lt;!ELEMENT titel (#PCDATA)&gt;
  &lt;!ELEMENT text (#PCDATA)&gt;
  &lt;!ATTLIST prior type CDATA #REQUIRED &gt;
  ]&gt;
  </code></pre>
  
  <p>Error Code in test.dtd</p>
  
  <blockquote>
    <p>The markup declarations contained or pointed to by the document type declaration must be well-formed. [2]</p>
  </blockquote>
  
  <p>Please help!!</p>