diff --git a/reference/datetime/datetimeinterface.xml b/reference/datetime/datetimeinterface.xml
index 0cd1d238641c..6c2cf86295c9 100644
--- a/reference/datetime/datetimeinterface.xml
+++ b/reference/datetime/datetimeinterface.xml
@@ -158,7 +158,7 @@
      <term><constant>DATE_ATOM</constant></term>
      <listitem>
       <simpara>
-       Atom (example: 2005-08-15T15:52:01+00:00); compatible with ISO-8601, RFC 3399, and XML Schema
+       Atom (example: 2005-08-15T15:52:01+00:00); compatible with ISO-8601, RFC 3339, and XML Schema
       </simpara>
      </listitem>
     </varlistentry>