<a name="boost.date_time.us_dst_trait.month_type"></a><span class="identifier">month_type</span><span class="special">;</span>                
  <span class="keyword">typedef</span> <span class="identifier">date_type</span><span class="special">::</span><span class="identifier">year_type</span>                        <a name="boost.date_time.us_dst_trait.year_type"></a><span class="identifier">year_type</span><span class="special">;</span>                 
  <span class="keyword">typedef</span> <a class="li