Ed Pentz, CrossRef1

The OpenURL and OpenURL Framework: Demystifying Link

ResolutionCrossRef, DOIs and OpenURL

Ed Pentz

Executive Director, CrossRef

epentz@CrossRef.org

Ed Pentz, CrossRef2

Overview

• What is a DOI

• Why CrossRef?

• Update on DOI developments

• How are DOI and OpenURL different?

• How do they work together?

• What does the future hold?

Ed Pentz, CrossRef3

Always Keep the End User in Mind

• “Electronic journals, e-print archives and print journals together are fulfilling the needs of readers. Scientists continue to read and today choose from alternatives that satisfy their specific needs and requirements, particularly to minimize their time and effort.” Carol Tenopir

• Collaboration and standards are critical

Ed Pentz, CrossRef4

What is a DOI?• A Digital Object Identifier (DOI), is a unique

string that identifies a piece of intellectual content

– Prefix is assigned by a Registration Agency (CrossRef)

– Suffix is assigned by publisher

– DOI is a “dumb” number

Ed Pentz, CrossRef5

dx.doi.orghttp://www.nature.com/cgi-taf/DynaPage.taf?file=/

nature/journal/v422/n6932/full/nature01566_fs.html

http://dx.doi.org/10.1038/nature01566

DOI Directory Prefix Suffix

Ed Pentz, CrossRef6

Why DOIs are good• A unique, persistent identifier but also…• An actionable identifier – a resolution system with

central resolution point• Governance (persistence)

– International DOI Foundation (IDF) – policies and standards for general DOI System; interoperability

– RAs - services using the DOI System, involved in IDF governance

The DOI Community

…and more !!…and more !!

CERN

…and more !!

• Gateway to the DOI world

• Develops and maintains the DOI standard

• Develops and maintains the Handle system upon which the DOI executes

Ed Pentz, CrossRef8

DOI Community Growing• 7 DOI Registration Agencies (including CrossRef) – scholarly

publishing, e-learning, UK/EU government, scientific data sets, etc

• 3 national libraries joined IDF as consortium – The British Library (UK), Die Deutsche Bibliothek

(Germany) and the Koninklijke Bibliotheek (The Netherlands)

• DTIC (Defense Technical Information Center) member of IDF• German National Library of Science and

Technology (TIB) – project to look at DOIs for scientific data sets

• The IDF is not just publishers

Ed Pentz, CrossRef9

CrossRef Mission Statement

• To provide services that bring the scholar to authoritative primary content, focusing on services that are best achieved through collective agreement by publishers

Ed Pentz, CrossRef10

What is CrossRef?• Non-profit membership association

– DOI Registration Agency for Scholarly Content• Registration of metadata and unique, persistent

identifiers• Representation on IDF Board, TWG and RAWG

– Reference linking service– Standards and Guidelines

• Rules governing metadata and linking• Guidelines – using DOIs in journals and citations

Ed Pentz, CrossRef11

What Does CrossRef do?• Makes reference linking easy and reliable for journals,

conference proceedings and books• Technology Infrastructure

• Persistent links using DOIs - no broken links in citations or database records (Average half-life of a URL is 44 days)

• Publishers update URLs in one location; about 50% of the records in CrossRef have already been updated

• Business Infrastructure– Membership agreement sets rules and creates level playing field– Business model neutral! PLOS and BioMed Central are members– no bilateral agreements needed – one agreement allows linking to over

200 publishers

Ed Pentz, CrossRef12

How CrossRef Is Used• By publishers…

– Deposit XML metadata for content– Parse references send to CrossRef to get DOIs– Make a reference link by sending the DOI to

http://dx.doi.org/

• By secondary databases and A&Is– Links from abstract records to full text

• By libraries…– Submit metadata to CrossRef to get DOIs to link to full

text (no cost)– Send DOI to CrossRef from local link server to lookup

metadata (no cost)

Ed Pentz, CrossRef13

How CrossRef Is Used

• Administrative issues with libraries – more automation needed

• By end users…– Click on DOI links in online resources (not

always aware it’s a DOI or CrossRef-enabled)

• Find DOIs using free form at CrossRef site

DOIs in Online Full Text

DOIs in Reference Citations

Ed Pentz, CrossRef16

DOIs as Article Locators

Ed Pentz, CrossRef17

DOIs in Google

Reference to article

Publisher Site

Ed Pentz, CrossRef18

Publish Ahead of Print

Ed Pentz, CrossRef19

Current CrossRef Stats

• 250 member publishers• 9.1 million DOIs (5 million last year)

• 8500 Journals (6500 last year)– Books and conferences starting to be added

• 3.9 million DOI clicks in September (7-fold increase since January 02 in DOI use – this is users clicking and traffic to publishers’ sites)

Ed Pentz, CrossRef20

CrossRef Fees• Libraries – free access since May 2003

– Interest in OpenURL integration (DOIs + metadata)

– 150+ libraries signed up

• Per DOI retrieval fee for members and secondaries will be removed starting in 2004 (revenue from annual membership fee and deposit fee)

• DOIs Everywhere is the goal

Ed Pentz, CrossRef21

DOIs and OpenURL• DOI and OpenURL are different types of things

with different purposes…but they work together• DOI: unique identifier, standardized metadata,

single point of resolution• OpenURL protocol supports a standard way to

transport metadata (which can include a DOI)• The OpenURL Framework enables context

sensitive linking through Local Link Resolvers• OpenURL is not about unique identifiers and it

doesn’t provide resolution

Ed Pentz, CrossRef22

OpenURL and DOIs/CrossRef

CrossRef helps solve the “appropriate copy” problem by providing a ‘reverse’ DOI lookup (DOI in / meta-data out)

http://doi.crossref.org/servlet/query?id=10.1006/jmbi.2000.4282&pid=<USR>:<PWD>

CrossRef offers an OpenURL 1.0 compliant resolver

http://doi.crossref.org/resolve?pid=<USR>:<PWD>&aulast=Maas LRM&title= JOURNAL OF PHYSICAL OCEANOGRAPHY&volume=32&issue=3 &spage=870&date=2002

(CrossRef returns DOI or will redirect to the target document)

OpenURL and DOI are complementary technologies

Ed Pentz, CrossRef23

CrossRef/DOI/OpenURL Linking

• Two distinct modes of integration:– CrossRef/DOI localization addressing the

“appropriate copy” problem– Article-level linking for CrossRef publishers

Ed Pentz, CrossRef24

Aggregator

LocalOPAC

CrossRef/DOI Linking

Ed Pentz, CrossRef25

OpenURL Aware

References

DOI Server

ServerDOI

OpenURL

Metadata

DOI link

http://www.sfx.edu/? doi=10.1034/j.1399-0039.2000.560502.x

http://dx.doi.org/ doi=10.1034/j.1399-0039.2000.560502.x

CrossRef, DOI and OpenURL

Ed Pentz, CrossRef26

Server

Metadata

DOI

DOI link

Links to Publishers

Ed Pentz, CrossRef27

Publisher Site

Local Link Server

Link Efficiency

Publisher Site

Publisher Site

Publisher Site

Publisher Site

Publisher SitePublisher Site

Publisher Site

X 250 sites

DOI Server

Ed Pentz, CrossRef28

Ed Pentz, CrossRef29

Multiple Resolution• Multiple URLs assigned to one DOI• Metadata labels associated with URLs• Relationships between DOIs captured in

metadata• Services associated with a DOI (mirror

copies, rights clearing, ordering print)• Local linking servers must be able to take

advantage of DOI MR services.

Ed Pentz, CrossRef30

Multiple Resolution XML

Ed Pentz, CrossRef31

Conclusion• Collaboration and standards are crucial to

serving end users• DOIs, CrossRef, OpenURLs and local

linking servers need to interoperate• In 2004 repeat the successful “appropriate

copy” project for multiple resolution– Link resolver vendors, publishers, CrossRef,

libraries all need to work together