At 03:53 PM 5/9/2003 -0400, you wrote:
>I can see your point.  But while it presents problems to have these
>kinds of links across records, is it not possible to establish this
>relationship -- between a work and its expression -- within a record?
>I have a sense this relates to my earlier questions about performances.
>  Can we distinguish in a MODS record between a play written by
>Shakespeare, and a specific performance of that play?

I don't see why not, but I'm totally unfamiliar with how one would catalog
a performance -- usually we'd be cataloging a fixation of a performance --
i.e. a video of it, or a sound recording. There are fields in MARC for
date, time and place, and performing arts libraries are able to do this
cataloging. However, the idea that the written version of a play and a
performance of that play would be in the same record is not one that is
included in any cataloging rules that I'm familiar with. Those would be
considered separate works. What links them is that they have the same
title, and perhaps the same "uniform title" (in library parlance). There's
no hard-coded linking; the meaning of the metadata allows humans to
understand what the intellectual links are.

kc