li>
          <li><a href="#instantiation_types">Instantiation types</a></li>
          <li><a href="#types">Nested types</a></li>
          <li><a href="#nested_templates">Nested class templates</a></li>
          <li><a href="#constructors">Constructors, copy and assignment</a></li>
          <li><a href="#index_retrieval">Index retrieval operations</a></li>
          <li><a href="#projection">Projection operations</a></li>
          <li><a href="#serialization">Serialization</a></li>
        </ul>
      