<a href=isbn:0-13-484080-1> Carl Malamud's "Stacks" </a>
to handle references to books. The hope (such as it is) is that
a browser will be able to take the isbn magic cookie and feed it
into a library on-line catalog and get a meaningful result back.
If there has been an SGML coding proposed or in use for MARC format
records that would be the appropriate way to return the results.
I don't have MARC details on-line, but that's OK since most library
on-line catalogs don't yet give you access to raw cards.
Until there's an isbn-to-www gateway they're still quite useful
as absolute reference markers, easy to get the full cataloging
information that way.
Similar treatment is expected for issn (serials) numbers. In some
distant far-off future electronic serials and electronic documents
will get card catalog entries for them if they're suitably permanent
and distinctive to warrant them. Until then there are plenty of books
out there that I'd like to have pointers to.
Bonus points if you can deliver fully formed hypertext to the
desktop based on the isbn number :-)
--Ed