<div class="citation">
  <p 
    tal:repeat="content python:here.viewable('p')"
    tal:content="structure content">
      bla fasel
  </p>
  <p class="author" 
    tal:repeat="content python:here.viewable('author')"
    tal:content="structure content">
      author
  </p>
  <p class="source" 
    tal:repeat="content python:here.viewable('source')"
    tal:content="structure content">
      source
  </p>
</div>
