r_month_day_base">year_month_day_base</a> <span class="special">{</span>
  <span class="comment">// types</span>
  <span class="keyword">typedef</span> <span class="identifier">YearType</span>  <a name="boost.date_time.year_month_day_base.year_type"></a><span class="identifier">year_type</span><span class="special">;</span> 
  <span class="keyword">typedef</span> <span class="identifier">MonthType</span> <a name="boost.date_time.year_month_day_base.month_type"></a><span class="identifier">month_type</span><