n><span class="special">,</span>
      <span class="identifier">boost</span><span class="special">::</span><a class="link" href="reference/add_reference.html" title="add_reference">add_reference</a><span class="special">&lt;</span><span class="keyword">const</span> <span class="identifier">T2</span><span class="special">&gt;::</span><span class="identifier">type</span> <span class="identifier">nsecond</span><span class="special">)</span>
<span class="special">:</span><span class="identifier">first</span><sp