@calendar indicates the system or calendar to which the date represented by the content of this element belongs, but this element has no textual content. The element should not be categorized in detail with @subtype unless also categorized in general with @type @targetLang can only be used if @target is specified. Only one of the attributes @target and @cRef may be supplied on . Only one of the attributes @target' and @cRef' may be supplied on An lg element must contain at least one child l, lg or gap element.