Be careful though, please don't send an rft_id ISSN identifier for an
_article level_ metadata package. OCLC does this. It's wrong, as the
ISSN does not serve as an identifeir for the _article_ cited, but rather
for the journal it's in. Until I figured out what was going on, this
caused some bugs in Umlaut.

It _would_ be nice to send multiple ISSNs even for an article-level
citation. Let's say the generator of the OpenURL happens to know that
there are several variant ISSNs for the publication, that identify
differnet manifestations, but any of which are valid for the given
article citation. It would be helpful for the generator to send them all
along, in case the link resolver knows about some but not all of them,
to increase the chances that the link resolver will properly 'recognize'
the citation.

But, it unfortunately can't be done. It's not the end of the world to
realize that OpenURL isn't perfect (what is? By trying you learn from
your experience to do better next time), but I'm unconvinced that this
is actually desirable in any way instead of an oversight. One thing I
think I feel like we've learned from many of our community's recent
metadata initiatives is the importance of creating standards in such a
way that they can be further developed and/or extended in a backwards
compatible way. Ie, an OpenURL 1.1 or something, that was backwards
comptable so it could be sent to resolvers that knew no more than 1.0
without problems. This has to do with both the design of the
structure/syntax of the metadata, as well as the design of the
_processes_ of maintenance, to make this kind of extension and
development not too cumbersome socially.


Karen Coyle wrote:
> Ah, you're referring to rft_id, and I was looking at the ISBN element in
> the KEV Book format. So using rft_id would work.
> The reason for multiple ISBNs is that many MARC records have ISBNs for
> the hard copy and the paperback. Without going through some gyrations
> you don't know which is which, although for purposes like ILL either is
> valid. There are also multi-volume works that each get an ISBN.
> Like other FRBR "levels" manifestation has a fairly wide range of
> ambiguity. A book simultaneously published in two countries... is that
> one manifestation or two? What if they each get a separate ISBN? A
> hardback and trade paperback that come out at the same time, where the
> only difference is the cover... and the ISBN?
> Although I often use the shortcut of "ISBN = manifestation" the fact of
> it is that ISBNs are publisher inventory and sales numbers and are used
> in ways that are convenient for publishers. They also get mis-assigned
> frequently, as some tests being run on bib data at the Open Library are
> showing.
> kc
> Ross Singer wrote:
>> Actually, this:
>> indicates that multiple rft_ids *are* valid, and, in fact, would have
>> to be, since you could very easily have a DOI and a PMID and, say, a
>> SICI.
>> I have no idea what any resolver would do with this bundle of ISBNs,
>> of course.  It also seems somewhat contrary to the intention of the
>> Book metadata format, since I think it's (in my murky view of FRBR-y
>> terms) trying to define a manifestation rather than the expression
>> level that Bill is trying to use it for.  I could be weaving in my own
>> interpretations and biases there.
>> An alternative would be use by-reference context objects and then make
>> the context objects available as XML.  You could have multiple context
>> object available in one XML document this way.  A combination of
>> COinS/unAPI could make something like this possible.
>> -Ross.
>> On Feb 18, 2008 6:53 PM, Karen Coyle <[log in to unmask]> wrote:
>>> Actually, the max occurrence of ALL of the KEV keys is 1 except for
>>> "au"
>>> (which is unlimited). I remember discussions in which we acknowledged
>>> that one key NE one value, eg you could input multiple values if your
>>> recipients were in agreements (a poor excuse, I know). Thus:
>>> "isbn:3333;isbn:8888". My only memory for why max=1 for all of these is
>>> that it has to do with the fact that there is no structure or
>>> dependency
>>> in KEV, so an OpenURL with keys
>>>      &
>>> isn't interpretable in terms of what authors go with what titles. Why
>>> the exception for au but for no other fields? My memory fails me here.
>>> Undoubtedly it made sense at the time.
>>> kc
>>> Jay Luker wrote:
>>>> Hi William,
>>>> According to the book KEV format (defined here:
>>>> ttp:// the max occurrence of the isbn key is 1. I'm
>>>> assuming that by extension that means that the rft.<m-key> (i.e.,
>>>> rft.isbn) form is also limited to one occurrence. So specifying
>>>> multiple ISBNs that way is a no go.
>>>> You can however specify multiple referent identifiers. From the KEV
>>>> Context Object format matrix ( "Multiple
>>>> instances of rft_id do not indicate multiple Referents, but rather
>>>> multiple ways to identify a single Referent"
>>>> So I *think* what you could do is this:
>>>> "rft_id=urn:isbn:<isbn1>&rft_id=urn:isbn:<isbn2>&..."
>>>> Also, I'd be remiss not to point you to a more authoritative list for
>>>> OpenURL questions:
>>>> Although I'm sure there's plenty of overlap in interest/knowledge in
>>>> the subject between the lists.
>>>> --
>>>> Jay Luker [log in to unmask]
>>>> Software Engineer, Ex Libris Inc.
>>>> (617) 332-8800, x604
>>>> On Feb 17, 2008 3:14 AM, William Denton <[log in to unmask]> wrote:
>>>>> I'm hep to the COInS scene now and am using it in some lists of
>>>>> books I'm
>>>>> generating.  For some of the books I know multiple ISBNs.  Can I
>>>>> include
>>>>> them all in one COInS span somehow?  Doing one individually makes my
>>>>> OpenURL Referrer extension clutter up the page with a lot of links.
>>>>> I looked at the specification but it didn't seem to cover this.
>>>>> only seems to want one one ISBN.  Putting
>>>>> multiple
>>>>> rft.isbn variables just makes the last one overpower the earlier
>>>>> ones.
>>>>> Any tips appreciated!
>>>>> Bill
>>>>> --
>>>>> William Denton, Toronto :
>>> --
>>> -----------------------------------
>>> Karen Coyle / Digital Library Consultant
>>> [log in to unmask]
>>> ph.: 510-540-7596   skype: kcoylenet
>>> fx.: 510-848-3913
>>> mo.: 510-435-8234
>>> ------------------------------------
> --
> -----------------------------------
> Karen Coyle / Digital Library Consultant
> [log in to unmask]
> ph.: 510-540-7596   skype: kcoylenet
> fx.: 510-848-3913
> mo.: 510-435-8234
> ------------------------------------

Jonathan Rochkind
Digital Services Software Engineer
The Sheridan Libraries
Johns Hopkins University
rochkind (at)