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We have
posted this article which appeared in the April 1, 2004 issue of Library Journal on OpenURL
linking as a service to our customers. Please note that WilsonWeb offers
OpenURL linking functionality that is part of our WilsonWeb online
database delivery system—at no additional charge!
Reprinted
with kind permission from Library Journal, April 1, 2004.
By John McDonald & Eric F. Van De Velde
Link resolvers are essential to getting optimal usage of
electronic content
One of the most innovative and revolutionary library
services to evolve in the Internet era is reference linking, the ability
to transmit bibliographic data through hypertext links and to connect
users with the full richness of electronic collections with ease. These
collections can include academic research journals, general interest
magazines, e-books, bibliographic indexes, and other reference works—as
well as the sources and services associated with those items. Reference
linking lets users move from an abstract from one publisher to the
full-text document in another vendor's database, from a bibliography in an
article to the library catalog, from one database to another, or from a
journal article to a web site.
Reference linking is necessary because library and
information users today expect to move seamlessly among library content
and information on the Internet. Libraries present users with disparate
databases, different user interfaces, various searching capabilities, and
changing institutional subscriptions. Reference linking is largely
succeeding in removing these barriers.
Resolving appropriate copy
By 1998, context-sensitive linking was a topic at library
conferences. Partial solutions had been proposed, but none could solve the
most vexing of problems: the appropriate-copy problem. This occurs when
linking from a third-party database to a resource (say, a journal) of
which one has multiple copies. Each of these copies is governed by
distinct access policies. Ideally, the links to this resource should
resolve to the copy that is appropriate to the particular user and
circumstance (the "context"). Problems stemming from owning multiple
access licenses to the same resource may seem limited to only the richest
of institutions (thus the nickname "the Harvard problem"), but they were a
stumbling block to development.
At this crucial time, Herbert Van de Sompel, then head of
library automation at the University of Ghent in Belgium, proposed a link
resolver managed by the library. Because the library knows its
collections, its policies, and its users, a library-managed link resolver
makes context-sensitive linking possible. In collaboration with Patrick
Hochstenbach, also then of the University of Ghent, Van de Sompel proved
the viability of the concept by implementing the SFX (named for special
effects) linking server. It was quickly recognized as the silver-bullet
solution. In October 1999, Van de Sompel along with Los Alamos National
Laboratory’s Rick Luce and Cornell University's Paul Ginsparg organized a
historic meeting, the Santa Fe convention. The meeting, best known for the
Open Archives Initiative, also put other digital library projects
including SFX on the national stage.
The Caltech experience
In early 2000, Ex Libris, known for its ALEPH Integrated
Library Catalog, acquired the rights to the software and beta tested with
a small number of U.S. libraries. The beta phase was designed to test the
viability of the reference linking concept and extend beyond early
experiments at Ghent with SilverPlatter databases. The California
Institute of Technology (Caltech) Library System got involved because Eric
Van de Velde returned from the Santa Fe convention convinced that Caltech
needed SFX.
Staff attended beta training at the Ex Libris offices in
Boston in 2000. Soon after, Betsy Coles, manager of digital library
systems, wrote the code that made reference linking possible from the ISI
Web of Science databases that the library had locally loaded. John
MacDonald, acquisitions librarian, uploaded the information about the
library's journal holdings to the resolver's database (now known as the
Knowledgebase).
Thereafter, Caltech focused on getting more information
providers to "enable" their databases to work with SFX and to create
linking syntaxes to other information resources. This was not always easy.
Many commercial providers met the request with either a quick denial or a
request for additional subscription payments for added services. In the
best cases, companies simply asked for information and clarification of
what they needed to "OpenURL enable" their databases.
Going live
After a year of testing and development, the resolver was
released to the campus community in April 2001. Initially, it allowed
users to link from an entry in the Web of Science to outside services,
including links to full–text articles in other databases, interlibrary
loan services, and search engines on the web. We opted for a "soft"
launch, with minimal advertising to the community. The release of SFX made
Caltech the first academic research institution in the United States to
have a resolver active in a production environment
Caltech patrons used the SFX links without delay and with
few problems. In fact, the first feedback we received was an inquiry about
adding additional full-text subscriptions. The second was to report a
problem the user had with the browser. Soon after, we began receiving love
letters from our patrons praising the new linking technology. Remarkable,
since we rarely hear from patrons unless something is wrong.
Content providers get on board
We hesitated about releasing the resolver without a
critical mass of both Sources and Targets. We feared that users would only
associate the resource with links to full-text articles from the Web of
Science. By April 2001, only EBSCO and Institute of Physics, among our
vendors, had OpenURL in production. Our patience was running out, and we
decided to release the service anyway.
After our release to the campus, other providers began to
OpenURL enable their products. By the end of 2003 most of our vendors were
enabled, with the exception of Innovative Interfaces, our integrated
library system. Innovative chose to require customers to purchase its
competing OpenURL resolver, WebBridge, before allowing OpenURL linking
from the catalog, and it remains the only major resource at Caltech that
is not a Source.
Caltech's Knowledgebase currently has 34 information
resources active as Sources and 95 active as Targets, encompassing nearly
6000 electronic books and 4000 full-text electronic journals. A smashing
success with faculty and students, it receives nearly 10,000 full-text
downloads per month, over a quarter-million articles over the past 28
months.
Other vendors arrive
ExLibris's SFX resolver was the first to the market, but
many other vendors now offer competition. Some are standalone products
used solely for resolving OpenURLs while others are integrated into OPACs,
proprietary databases, or other services. In addition, there are
individual efforts underway to build resolvers locally using OpenSource
software. The major standalone resolvers are SFX from ExLibris, Endeavor's
LinkFinderPlus, Journal Finder from the University of North
Carolina–Greensboro, Gold Rush from CARL, SirsiResolver from Sirsi,
Fretwell-Downing's OL², 1Cate from Openly Informatics, Serials Solutions's
ArticleLinker, and LinkSource from EBSCO.
Many of these vendors offer an ASP option, which means
that the resolver is hosted by the vendor, with support in establishing
the "opening-day collection" for the Knowledgebase and assistance with its
continuing maintenance. Many also offer the products as software with
annual maintenance fees. This allows the library to run the resolver on
its own hardware and retain local control.
While most OPACs are now OpenURL enabled as both Sources
and Targets, some go a step further and integrate an OpenURL resolver
directly into their products. Both Innovative with its WebBridge product
and Dynix with Horizon Link offer this option.
In addition, content providers are building OpenURL resolvers into their proprietary database systems. Companies such as H.W.
Wilson and Cambridge Scientific Abstracts have OpenURL links built into
their database interfaces. This allows users who do not have OpenURL
resolvers to still use OpenURL technology to build additional services, as
predefined by the database vendors themselves.
For help determining which product is right for your
library, see "Considering a Resolver?" on p. 34. But some libraries might
want to build their own. Several libraries with the technical staff and
motivation have opted for this solution. It offers a few advantages over
commercial resolvers, especially greater flexibility. "First of all,
building our own resolver enables us to load our Knowledgebase to suit our
own situation," says Mark Dahl, library technology coordinator at Lewis &
Clark College, Portland, OR. "It also allows us to share our resolver with
campus libraries."
The resolver experience
As an initial beta-tester, Caltech had a unique
experience. More recent implementers, such as the library at Macalester
College, a small liberal arts school in St. Paul, are more typical. Angi
Faiks, collection management team leader at Macalester, has found linking
technology enhances the scholarly process. "We can say with certainty that
you don't have to be a large, research-focused, graduate-level institution
to take advantage of what OpenURL has to offer," says Faiks. Macalester
launched SFX over two years ago using the ASP model.
The service has been popular, with over 1000 SFX requests
made daily in 2003. Faiks reports that they have greatly reduced the
number of interlibrary loan requests, a side benefit to connecting to
resources in disparate databases. "Plus, by populating our loan request
forms with accurate citation information we have saved a great deal of
time," says Faiks. Macalester manages its Knowledgebase with a single
staff member who had SFX maintenance added to previous duties. "Even in
tough budget times, this is money well spent," adds Faiks.
The University of Richmond, VA, implemented Endeavor's
LinkFinderPlus in fall 2002 after a fast-track implementation of
just under a month. Like Faiks, Rachel Frick, Richmond's head of
bibliographic access services, believes their linking tool "increases the
value of our e-resources by increasing their usage." Frick also has no
concerns about the flexibility. "We have customized our interface," she
says. "We also are in the process of adding a search for author or title
to run through the information in OAIster [a metadata harvester for
depositories in the Open Archives intitiative]. It is this type of search
that brings together the power of OpenURL with the powerful idea of open
access materials."
Not just academics
Customers for link resolvers are as diverse as theological
schools, historical societies, and special libraries. Susan Scheiberg,
assistant library director, RAND Corporation, says that their
implementation of Serials Solutions' ArticleLinker resolver
"revolutionized our library service in about 15 minutes." Scheiberg was
initially attracted to the product because she was an existing Serials
Solutions customer and because of the product's low cost. With the
ArticleLinker up and running, Scheiberg feels that staff and patrons can
better identify the disparate databases that the library purchases but
also maximize use of full-text databases, online journals, and abstracting
and indexing databases.
Even with this good news, public librarians have been slow
to implement link resolvers, something that baffles most vendors. It is
crucial that public libraries use link resolvers, argues Peter McCracken,
cofounder of Serials Solutions, especially since public libraries often
offer large journal collections provided through statewide contracts.
Perhaps public libraries have been put off by the technological
investment, although McCracken points out that an ASP solution is perfect
for small and medium-sized public libraries.
Future of linking
It is safe to guess that in the not-too-distant future
every library with a digital collection will provide an OpenURL resolver
for its users. As a rule, the OpenURL resolver becomes an essential part
of the digital library infrastructure within months of deployment. Users
depend on it, and librarians insist on its reliable availability. The
future of resolvers in digital libraries is secure, at least until a
substitute technology comes along.
The question that remains is whether this technology will
find its niche outside of library applications. The NISO (National
Information Standards Organization) standardization committee certainly
thought so when it transformed the basic OpenURL idea into the OpenURL
Framework last year. The Framework is agnostic as to application domain,
which means it can be applied to other industries. For example, the real
estate industry could define metadata and identifiers for houses,
realtors, buyers, sellers, various contracts, and more–creating a whole
new set of applications.
Van de Sompel, now at the Research Library at the Los
Alamos National Laboratory, puts it as a challenge to NISO. "The committee
has made sure that this generic specification is readily implementable in
the community in which OpenURL emerged. However, whether this enormous
endeavor will succeed will depend on whether other communities discover
and adopt the standard. I feel that NISO has an important role...promoting
a NISO specification beyond the typical NISO constituency." The OpenURL
Framework standard is ready for a few enterprising individuals to use it
to explore whole new worlds.
Author Information: John McDonald (jmcdonald@library.caltech.edu)
is Acquisitions Librarian and Eric F. Van de Velde (evdv@library.caltech.edu)
is Director of Library Information Technology, California Institute of
Technology, Pasadena
Link Resolver 101
A student searching through
PubMed finds a citation to an article she wants to read. But how to locate
a copy? Researchers today are faced with questions that range from whether
the journal is available online to whether their library has a
subscription (either print or online), from wondering if the journal may
be in an aggregated collection to whether (and how) a copy can be obtained
through interlibrary loan.
It is difficult to answer
these questions through conventional web links. After all, how would
PubMed know to which other services the student has access? It all depends
on the student's affiliation.
Link resolver software
brings together information about the cited resource, the user, and the
library's many subscriptions, policies, and services. For the software to
work, the content providers must be willing to participate as Sources
(databases or sites that can provide a link from a reference). To make
linking more reliable, it helps if providers collaborate as Targets (the
end results, usually a full-text article or a search for print holdings in
the library's catalog). Also, the library needs to load accurate data
about its holding into the link resolver's Knowledgebase.
The link resolver becomes
activated when the user clicks on a link or button ("Search for full
text") embedded in the user interface of PubMed (or other services). Using
the OpenURL Framework, information, such as the metadata for that
citation, is bundled together from the Source and sent to the resolver
software that will process the data, comparing it to the Knoweldgebase.
As a result, the student is
then presented with a range of options for locating the article. If the
library has an online subscription, the Target may link to the article
itself or to the journal. Other options include the library's print
holding for that title, or interlibrary loan or document delivery options.
Considering a Link Resolver?
Librarians who want to add
an OpenURL resolver to their library services should evaluate not only the
product but how it meets their local needs. Harry Samuels, product manager
for Endeavor's LinkFinderPlus,
has developed a list of things to consider.
First, the link resolver
must be OpenURL-compliant to work with the vast majority of information
resources in the market today. It should also be available as a standalone
product so that the library has maximum flexibility in choosing the best
solution for each piece of the digital library puzzle.
Decide whether you want to
purchase a system that is run and managed locally or one that is a
subscription service hosted by the vendor. A subscription service may be
more feasible for customers with limited technical staff or hardware
resources, while a locally run system gives the library maximum
flexibility and control. Make sure that any subscription service selected
is hosted at a professional hosting site with 24/7 support and redundant
connectivity to the Internet. Locally run resolvers should be able to run
on several different operating systems and use well-known, commercially
viable components that can easily be supported.
Carefully evaluate the
product's Knowledgebase and match your own collections to the Sources and
Targets with which the resolver functions.
Will you want to customize
the product interface? Some products allow significant customization;
others may not. Customization of both the interface and the product itself
might be important for some libraries. You may want to restrict some
services, empower other services, or develop new ones.
Most importantly, consider
a product's overall price. Not all resolvers are affordable for all
libraries.
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