I see that http://www.tei-c.org/release/doc/tei-p5-doc/en/html/ref-att.datable.w3c.html makes multiple references to "the W3C XML Schema Part 2: Datatypes Second Edition". We should also add a link to this document: it appears to be at http://www.w3.org/TR/xmlschema-2/ .
At times the reference to this document is accompanied by one of the following:
a) "temporal expression"
b) "W3C date, time, and date & time formats"
c) "using the Gregorian calendar"
We should be a bit more consistent in our language. Specifically:
a) The W3C recommendation doesn't use the term "temporal expression", so perhaps we should replace this with "the primitive datatypes defined in Appendix D".
b) I suspect "date & time" is supposed to refer to what the W3C recommendation calls "dateTime".
b) "using the Gregorian calendar" seems redundant since as far as I can tell the W3C recommendation refers only to the Gregorian calendar.
Furthermore, I suggest that at http://www.tei-c.org/release/doc/tei-p5-doc/en/html/ref-att.datable.iso.html we drop the phrase "Any string representing a valid date, time, or one of a variety of combinations." since it's misleading given that it's followed by a note: "The value of the when-iso attribute should be the normalized representation of the date, time, or combined date & time intended, in any of the standard formats specified by ISO 8601, using the Gregorian calendar."