title: Exclude specific tag from selection in XPath
body: <p>I know this is a simple question, but I can't figure it out.
  Consider the following simple XML document:</p>
  
  <pre><code>&lt;root&gt;
    &lt;a&gt;&lt;/a&gt;
    &lt;b&gt;&lt;/b&gt;
    &lt;c&gt;&lt;/c&gt;
    &lt;a&gt;&lt;/a&gt;
    &lt;d&gt;&lt;/d&gt;
    &lt;e&gt;&lt;/e&gt;
    &lt;a&gt;&lt;/a&gt;
    &lt;a&gt;&lt;/a&gt;
  &lt;/root&gt;
  </code></pre>
  
  <p>What's the best way to select the nodes <code>&lt;b&gt;</code> through <code>&lt;e&gt;</code> using XPath?</p>
  
  <p>I'm looking for something like</p>
  
  <pre><code>/root/*[not(a)]
  </code></pre>
  
  <p>(which does not do the trick)</p>