CITATION LINKING AND THE E-JOURNAL

LANDSCAPE

April, 2000

BACKGROUND ASSUMPTIONS

Linking is a core function, not an incidental add-on.

The web environment is built around easy navigation between related digital resources.

If an information resource is not accessible through links, its value decreases.

E-JOURNALS AND LINKING

• Journal literature is almost a poster child for for web-linking– Through citations one traces the “web” of

thought on a subject

• The value of an e-journal system will depend on its participation in the inter-linked e-journal environment

Citation LINK

MAGICLINK

Cited Article

Citation

WHAT WE ARE TRYING TO ACCOMPLISH

CLICK

Any old system

WHAT MAKES MAGIC HAPPEN?

• Somehow “any old system” must get a useable link into the citations it delivers

• Currently there are 2 major approaches to creating links– “algorithmic”– “name-based”

ALGORITHMIC LINK CREATION

• Links are built by knowing how to predict the URL for a specific journal article– Link-builder parses citations to determine title,

volume, and page information for use in URL– Link-builder knows URL format for each journal

title and access system

• Dominant mode of creating links today– Used by ISI, Ovid, SilverPlatter, etc– S-Link-S product helps build links

ALGORITHMIC LINK ISSUES

• Not every site has algorithmically predictable URLs

• How many algorithms do you need? • How many systems need to build algorithms?• High maintenance because of constant

change• Does this scale???

NAME-BASED LINKS

• Each article is given a unique identifier

• Database available to provide identifier look-up from citation data– Either manually or by computer program– Done ahead of time by systems providing links

• At the time of use, the identifier is converted into an address through a “resolution server”

• DOI is prime example today

Any old system

CitationDOI

Step1

Step2 DOI Resolver

DOI

URL

Cited article

Search response

RepositoryURL

Article

Step3

FROM DOI TO ARTICLE

“NAMING” IS A POWERFUL SOLUTION

• Instead of a vast number of algorithms, a small number of places to look-up links

• Linked-to resources can freely move about without breaking links scattered across many systems

BUT -- WHAT IF MORE THAN 1 COPY EXISTS?

• Elsevier journals, for example, are available from– Elsevier ScienceDirect– OhioLink– University of Toronto

WHICH URL?

HandleServer

DOI

URL?

Sciencedirect.com?

Ohiolink.edu?

Utoronto.ca?

A PROBLEM

• DOI today cannot resolve to more than 1 copy

• DOIs have been devised specifically for publisher use in selling electronic publications on the net – They currently resolve to only the publisher’s

address!

CROSSREF

• CrossRef is largely based on the DOI– Major service is to provide a citation-

information-to-DOI look-up service

• Should generate a rich set of links between e-journal articles– But…it will only work for publisher’s copy!

• OhioLink and Toronto users will get links to Science Direct, not to local copies

THE APPROPRIATE COPY

• When more than 1 copy exists, specific populations have the right to access specific copies– Some systems today can do this sort of linking

(ISI), but it must be done by EVERY system from which links can come to work properly

– Today, only a few systems do this -- can we expect every journal publisher to do this for every subscriber?

WHY MULTIPLE COPIES WILL OCCUR

• “Local loading”– A number of institutions are already loading e-

journals for their local populations• OhioLink, Toronto, University of Illinois...

• Aggregators– Most electronic journal access in many

institutions today is through aggregators• OCLC EJO, EBSCO, Ovid, IAC, Bell & Howell

WHY MULTIPLE COPIES (continued)

• Mirror sites???– Which mirror you should use can depend on

“where” you are on the net• Some universities have had trouble getting the

appropriate mirror site configured

• Alternate “free with subscription”copies– Elsevier has alternate sites from ScienceServer

for these...

WHY MULTIPLE COPIES (continued)

• E-print archives– A lot of current interest in building subject-specific

e-print collections (which include published articles)• LANL, PubMedCentral, (CDL, Cornell, MIT...)

• Archiving– Institutional failure is as great a danger as

technological failure, – Multiple copies held by different parties is the best

protection

WILL THE ENVIRONMENT BE CONSTRAINED?

• A generalized link-from-anywhere-to- anywhere solution will allow the e-journal environment to evolve naturally

• We are in a period of much necessary experimentation– Who are the players?

– What are their roles?

– How many options will libraries have?

• Too early to constrain the options!!!

CURRENT DLF INITIATIVE

• Group approach to CrossRef (and now DOI Foundation) on this issue– Many examples of content legally available to

our populations that will not be linked-to in the current CrossRef/DOI infrastructures

– Have offered to help explore solutions, and to serve as test-beds when appropriate

ICOLC IMPLICATIONS

It is IMPORTANT that libraries (and consortia!)

let publishers know that they CARE about robust linking!