Defines the day(s) of the week on which a recurring <a class="localLink" href="http://schema.org/Event">Event</a> takes place. May be specified using either <a class="localLink" href="http://schema.org/DayOfWeek">DayOfWeek</a>, or alternatively <a class="localLink" href="http://schema.org/Text">Text</a> conforming to iCal's syntax for byDay recurrence rules