output"><span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span></code> that
      can hold reference types!
    </p>
<p>
      This same extension could have been done using partial template specialization
      of <code class="computeroutput"><span class="identifier">pair</span></code>, but to specialize
      <code class="computeroutput"><span class="identifier">pair</span></code> in this way would require
      three partial specializations, plus the primary