data.temporal.iso

data.temporal.iso defines the range of attribute values expressing a temporal expression such as a date, a time, or a combination of them, that conform to the international standard Data elements and interchange formats – Information interchange – Representation of dates and times.
Moduletei — 1 The TEI Infrastructure
Declaration
data.temporal.iso =
   xsd:date
 | xsd:gYear
 | xsd:gMonth
 | xsd:gDay
 | xsd:gYearMonth
 | xsd:gMonthDay
 | xsd:time
 | xsd:dateTime
 | token { pattern = "[0-9.,DHMPRSTWYZ/:+\-]+" }
Note
If it is likely that the value used is to be compared with another, then a time zone indicator should always be included, and only the dateTime representation should be used.
For all representations for which ISO 8601 describes both a basic and an extended format, these Guidelines recommend use of the extended format.
While ISO 8601 permits the use of both 00:00 and 24:00 to represent midnight, these Guidelines strongly recommend against the use of 24:00.