title: Error in dtd validation : A ')' is required in the declaration of element type "Bibliography"
body: <p>The error comes up on my editix editor for the first line below. Just cannot see why a ) is needed.</p>
  
  <pre><code>&lt;!ELEMENT Bibliography (Conference paper,Book,Book chapter,Journal article)&gt;
  &lt;!ATTLIST Author Title Year CDATA#REQUIRED&gt;
  &lt;!ELEMENT Conference paper (Author,Title,URL)&gt;
  &lt;!ELEMENT Author #PCDATA&gt;
  &lt;!ELEMENT Title #PCDATA&gt;
  &lt;!ELEMENT URL #PCDATA&gt;
  </code></pre>