A point in time recurring on multiple days in the form hh:mm:ss\[Z|(+|-)hh:mm\] (see [XML schema for details](http://www.w3.org/TR/xmlschema-2/#time)).

A date value in [ISO 8601 date format](http://en.wikipedia.org/wiki/ISO_8601).

A combination of date and time of day in the form [-]CCYY-MM-DDThh:mm:ss[Z|(+|-)hh:mm] (see Chapter 5.4 of ISO 8601).