title: XPath query to select element by certain implementation
body: <p>what is the correct query to select the the "<strong>Abstract</strong>" Node which is implemented by <strong>XYZImpl</strong> from <strong>http://www.namspace.org/impl</strong>? </p>
  
  <pre><code>&lt;...&gt;
    &lt;Abstract xmlns:q3="http://www.namspace.org/impl"
                  xsi:type="q3:XYZImpl"&gt;
      &lt;...&gt;&lt;/...&gt;
    &lt;/Abstract&gt;
    &lt;Abstract xmlns:q8="http://www.namspace.org/another"
                  xsi:type="q8:XYZImpl"&gt;
      &lt;...&gt;&lt;/...&gt;
    &lt;/Abstract&gt;
   &lt;/...&gt;
  </code></pre>
  
  <p><strong>order</strong> and namespace <strong>prefix</strong> are <strong>not</strong> under my control</p>
  
  <p>If the document just contains unique implementations the following query "works":</p>
  
  <pre><code>//Abstract[contains(@xsi:type,'XYZImpl')]
  </code></pre>
  
  <p>but I am searching for the right specification for the <strong>full qualified Name</strong> (namespace + Name)... :/</p>