diff --git a/reference/datetime/dateperiod/construct.xml b/reference/datetime/dateperiod/construct.xml
index d60f5db13a..5d6d28faf9 100644
--- a/reference/datetime/dateperiod/construct.xml
+++ b/reference/datetime/dateperiod/construct.xml
@@ -81,7 +81,7 @@
      <term><parameter>options</parameter></term>
      <listitem>
       <para>
-       Can be set to <constant>DateTime::EXCLUDE_START_DATE</constant>.
+       Can be set to <constant>DatePeriod::EXCLUDE_START_DATE</constant>.
       </para>
      </listitem>
     </varlistentry>