.apache.lucene.search.similarities"><code>TTF</code></a>: <code>F<sub>w</sub>/N</code> or
                 average number of occurrences of w in the collection</li>
         </ul>
     </li>
     <li><a href="http://lucene.apache.org/core/5_1_0/core/org/apache/lucene/search/similarities/Normalization.html?is-external=true" title="class or interface in org.apache.lucene.search.similarities"><code>normalization</code></a>: Term frequency normalization 
         <blockquote>Any supported DFR normalization list