<literal>minutely</literal>,
<literal>hourly</literal>, <literal>daily</literal>,
<literal>monthly</literal>, <literal>weekly</literal>,
- and <literal>yearly</literal> or
- <literal>annually</literal> may be used as calendar
- events which refer to
+ <literal>yearly</literal>,
+ <literal>quarterly</literal>,
+ <literal>semiannually</literal> may be used as
+ calendar events which refer to
<literal>*-*-* *:*:00</literal>,
<literal>*-*-* *:00:00</literal>,
<literal>*-*-* 00:00:00</literal>,
<literal>*-*-01 00:00:00</literal>,
- <literal>Mon *-*-* 00:00:00</literal>, and
- <literal>*-01-01 00:00:00</literal> respectively.
+ <literal>Mon *-*-* 00:00:00</literal>,
+ <literal>*-01-01 00:00:00</literal>,
+ <literal>*-01,04,07,10-01 00:00:0</literal> and
+ <literal>*-01,07-01 00:00:00</literal> respectively.
</para>
<para>Examples for valid timestamps and their