I tend to think of a Bibframe instance as an edition, but the Bibframe
instance seems to be something different, mainly in envisioning more
than one instance per edition, but occasionally more than one edition
per instance, using ISBN as the determining factor.

Often different bindings of copies of an edition have separate ISBNs,
but Bibframe says one instance per ISBN.  Since binding is normally
not mentioned in description (using "description" in its usual sense,
not to mean abstract or summary), how would these instance
descriptions differ from each other for the trade, library, deluxe,
paperback bindings?  One could have four Bibframe instances for one
AACR2 or RDA edition.

Often editions are published simultaneously by two or more publishers,
but Bibframe says an instance can only have one publisher.  Sometimes
these simultaneous publications have both or more publishers given in
the resource.  If both or more publishers appear, surely both or more
should be included in one instance description, even if each publisher
assigns its own ISBN?  Each ISBN describes the same resource; the only
difference is who sells it.   An instance description with one
publisher and one ISBN would not match any existing bibliographic
item, each item having more than one.

Occasionally publishers repeat an ISBN in difference editions.  Are
these two dr more editions to be one instance?  Which edition would be
described?  How does one handle both in the same collection with only
one instance description?  Rarely the same ISBN can appear in editions
of different works.

ISBN is not a safe litmus for determining editions (instances).

How do yearbooks or multivolume sets, with an ISSN for the serial, an
ISBN for the set, but individual ISBNs for the serial and set volumes,
fit into this?  (Utlas had 021 for analytical ISBNs of volumes within
a serial or set, a feature we still miss.)  While for ebrary, we must
create a record for each volume of a mutlivolume set or a serial,
because they can have only one 856$url per record, that is not
something we would like to do for all.  It would clutter up
catalogues.  BTW, can an instance record have multiple PDF URLs?

If these volumes with their own ISBNs are separate instances, are each
instances of a separate work, or are all volumes instances of a single
set or serial work?  Instance records for these volumes would seem to
have more in common with MARC item records, than AACR2/RDA MARC
manifestation records.

The Bibframe provisions seem to me not to accord with messy
bibliographic reality.

   __       __   J. McRee (Mac) Elrod ([log in to unmask])
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