Kelley McGrath <[log in to unmask]>
There is now also a $v in some authority record fields for a source of information for a specific data element. I think this is supposed to contain a citation, although I wasn't able to find an example in the documentation. This is more granular, but it's not clear to me if it's more machine-interpretable.
I'm not aware of any examples either, though I've mocked up one for a training session last year. The $v--and $u--appear to exist to accommodate those instructions found for several RDA elements in ch. 9-11 (headings and descriptions of persons, families, and corporate bodies) and a couple under ch. 6 (headings and descriptions of works and expressions) that call for posting the source of the information recorded, e.g., "Indicate the source from which the information on the gender of the person was derived applying the instructions given under 8.12." RDA 8.12 goes into a little more detail on how to post such sources. All of the examples given there at present, however, mirror the approach now taken with the 670 and 675 field content; the examples lack a greater variety of approaches to citing this information, as might be found in the $v and $u.
It wouldn't surprise me if NACO folks are already looking into if and how to use the $v and $u for element-level provenance.