Reference Linking via CrossRefApril 13, 2000

Ed PentzExecutive Director

CrossRef

Reference Linking

• Next frontier in journal publishing• End user access to logically related articles

in one or two clicks• Linking allows body of primary literature as

group of logically associated articles

Reference Linking

• End Users (researchers and scientists) pursue inquiries in a logical, sequential way

• Researchers want everything to link• Researchers expect everything to linkLinks Add Value

Why CrossRef?

• Current Linking– Between Secondary and Primary– Within online systems (HighWire)

• Linking Agreements – Bilateral - Secondary to Primary– Define terms of linking– “no surprises”

Why CrossRef?

• 1/2(N)(N-1) problem• 2-party agreements not scaleable

– too many publishers– too many linking schemes

• Result - Cooperation among publishers• CrossRef makes broad-based linking

manageable

CrossRef Goals

• Enable Reference Linking– initial focus on primary article to primary article

links (one or two clicks)– X to primary article links important– Primary article to X links– X = A&I Databases, Local Catalogs/Holdings,

Conference Proceedings, Reference Works• Broad-Based, Not-for-profit initiative

– All scholarly publishing

CrossRef Principles

• Aggregation (collect full text content)– duplicate/missing content/no “one stop shop”

• Gateway (Collect “less-than-full text”)– various models - some add value some don’t

but always lead to full text content• Distributed (Virtual) Aggregation

• ‘minimal’ centralized date - full text remains on publishers’ site

• access to full text determined by publisher

Reference Linking Infrastructure

• Article identifiers• Resolution system• Technical Infrastructure

– software & services• (Meta) Data Rules• Business Rules

Article Identifier• Digital Object Identifier (DOI)

– just the number– unique, persistent, managed by IDF– identifies Intellectual Property, not a location

(URLs)– NISO standard

• 10.1006/jmbi.1999.2736

• http://dx.doi.org/10.1006/jmbi.1999.2736

Prefix Suffix

Online Journal 1

End User

DOI Directory (Handle System)

Online Journal 2

1. User Gets Article

2. User Clicks DOI

3. URL Returned

4. User Gets Cited Article

DOI Resolution - IDF System

DOI Lookup - CrossRef System

• DOI-X Prototype (AAP/IDF/CNRI)• Reference linking prototype• Metadata

– Data Rules/XML DTD• Metadata Database (MDDB)• Reference Resolver (RR)

– Academic Press/Wiley– DOI Lookup/Matching

Metadata Deposit• Publishers submit article metadata

– Journal Title, ISSN/Coden,Volume, Issue, First Page, First Author, Year - mandatory

– Article Title is optional• XML-based DTD (DOI-X)

– Formal grammar – Supplementary “data rules”

• Journal articles today– Other genres to follow

Metadata Submission

Article Metadata (XML)

CrossRef Collection Service

CrossRef MDDBfor DOI Lookup

DOI Directory

DOI + URLArticle Data

DOI Lookup

• Publishers submit references to Reference Resolver (RR)– References tagged in SGML/XML– Minimum Data

• Abbreviated title, volume, first page - possibly first author and year

– Send Batches of References– RR - intelligent “link agent”

Business Rules/Governance

• CrossRef Membership– Primary scholarly publishers– Deposit metadata/Add links to references– Provide full bibliographic citation for

incoming DOI links– many publishers will give free abstracts– information on acquiring article (pay online,

document delivery, subscription)• CrossRef guarantees links

Organization

• Publishers International Linking Association (PILA)

• not-for-profit corporation to run CrossRef

• non-members can use system

• Close association with International DOI Foundation

• Incorporated Feb 2000• Executive Director, Board of Directors

Board of Directors

• AAAS (Science)• Academic Press

(Harcourt)• American Institute of

Physics• ACM• Blackwell Science• Elsevier Science

• IEEE• Kluwer Academic• Nature• Oxford University

Press• Springer Verlag• John Wiley & Sons

Members• AAAS (Science) • Academic Press (Harcourt)• ALPSP • American Institute of Physics • American Mathematical Society • American Psychological Assoc• ACM • Blackwell Science • CAB International• Cambridge University Press • Elsevier Science • IEEE

• Institute of Physics • Kluwer Academic • Marcel Dekker • Nature • Oxford University Press • Portland Press • Royal Society of Chemistry • Springer • Taylor & Francis • Thieme Verlag • University of Chicago Press • John Wiley & Sons • World Scientific

CrossRef Fees

• Member Fee• Annual Administrative Fee• Deposit Fee• Lookup Fee• Principles

• cost recovery

• flexibility

• no charges to end users to follow links

Fees

• Primary Publisher Annual Member Fee• 1 title, max 500 articles per year

$200• 2-5 titles, max 2,500 articles per yr

$500• 6-20 titles, max 10,000 articles per yr $750• 21-100 titles, max 50,000 articles per yr

$1,000• >100 titles or >50,000 articles per yr $2,000

Fees

• Non-Member Annual Administrative Fee• Secondary, database <100,000 records/yr $2,000• Secondary, database >100,000 records/yr $5,000• Agents $5,000 • Non-resellers (e.g., libraries) $300

Fees

• Deposit Fee for Primary Material• Current Year -- full text $0.60• Back File (deposit after 10/1/2000) $0.10• Back File (prior to 10/1/2000) $0.05

Fees

• Member Retrieval Fee (for successful match)• Current File $0.10 • Back File $0.05

• Non-Member Retrieval Fee (for successful match)• Secondaries & Agents, Current $0.10 • Secondaries & Agents, Back File $0.05• Non-reseller (libraries) $0.05

CrossRef and Libraries

• Libraries can use CrossRef system directly– submit metadata queries to get DOI– $300/year - $.05 per DOI matched

• Intermediaries can use CrossRef system • DOIs in place when content gets to libraries• Bibliographic metadata standards will

streamline content syndication

Future Developments

• Multiple Resolution– one DOI = one URL is starting point– multiple locations and multiple files

• Appropriate Copy Issue• Interoperability

– Metadata is “system neutral”• Collaboration - CrossRef wants to work with

libraries and other parties to address these issues

Publisher CopyLocal Copy

Aggregator CopyA&I Record

Contact Details

• www.crossref.org• Ed Pentz - epentz@crossref.org