FAQ for the use of CrossRef DOIs
Information for the use of CrossRef DOIs at Helmholtz centers
Author: Helmholtz Metadata Collaboration, Hub Earth and Environment
(https://earth-and-environment.helmholtz-metadaten.de)
Who is this document for?
For repositories, data stewards, libraries (CrossRef)
What is this information sheet about?
This information sheet covers the practical implementation and integration of Crossref DOIs in the data infrastructures of Helmholtz centers.
What do we recommend for implementation in the Helmholtz community?
We recommend the following for implementing Crossref DOIs:
If this has not already been done by the publisher, we recommend that all Helmholtz repositories register all journal articles with Crossref no later than at the time of submission and register a Crossref DOI.
We also recommend submitting complete metadata to Crossref and keeping it up to date at all times.
We further recommend that data and publication repositories always refer to publications via the Crossref DOI.
What is a Crossref DOI?
The Crossref DOI is a permanently resolvable DOI for scholarly publications (scholarly content), registered with Crossref, a DOI registration agency of the International DOI Foundation (IDF) (CrossRef, DOI Registration Agencies). The Crossref DOI is a persistent identifier (PID), i.e., a permanent, globally unique reference that points to reliable metadata and/or the current location of publications.
What is the Crossref DOI used for?
The Crossref DOI is used for citation, discovery, and linking of scholarly publications; Crossref stores and distributes metadata (including funding, licenses, ORCID, references) that can be discovered via Crossref DOIs, and operates search and API services. (CrossRef Content Registration)
Which organization is behind the Crossref DOI?
Crossref is a non-profit membership organization and DOI registration agency (RA) under the umbrella of the International DOI Foundation (IDF). (CrossRef Membership Terms, DOI Registration Agencies)
Why is the use of Crossref DOIs important for the Helmholtz community?
Standardized publication IDs with rich metadata facilitate publication discovery, reporting, evidence/proof, reference networks (Cited-by), corrections (Crossmark), and interoperability with ORCID and ROR. (CrossRef Documentation on Updating Metadata) This supports the implementation of the FAIR principles.
Where and how is the Crossref DOI registered?
Crossref DOIs are registered via Crossref Content Registration: web deposit form, XML deposit, or other methods; a membership (prefix) is required. (CrossRef Content Registration)
Who is responsible for maintaining Crossref DOI records for publications?
The registering organization (member/publisher/repository) – it must keep metadata and the target URL up to date. (CrossRef Documentaion on Maintaining Metadata, Resource Resolution URL Guide)
Where and how do I change Crossref DOI records?
By submitting a metadata update (re-deposit/re-submit) or—if only the URL needs to be changed—by providing a list to Crossref support; the DOI itself remains stable. (CrossRef Documentation on Updating Metadata, Resource Resolution URL Guide)
How do I know the Crossref DOI of a specific publication?
Via the publication landing page or the Crossref Metadata Search; it can also be queried via the REST API. (CrossRef Metadata Search, CrossRef REST API)
How do I find out which publication is behind a specific Crossref DOI?
Simply resolve the DOI (https://doi.org/...) – it leads to the landing page; details are also available via the Crossref REST API. (CrossRef REST API)
Who owns a Crossref DOI record?
It is part of the open Crossref registry. The metadata can be used under CC0; stewardship (maintenance/updates) lies with the registering organization. (www.crossref.org[1])
Are there alternatives to Crossref DOIs?
Yes: other DOI RAs (e.g., DataCite, JaLC, KISTI, ISTIC …) as well as non-DOI PIDs (Handle, ARK, URN). For scholarly journal articles & books, however, Crossref is the de facto standard. (DOI Registration Agencies, CrossRef DOI Prefixes)
What else are Crossref DOIs used for besides publications?
In addition to journal articles/books, also for preprints/posted content, standards, reports/working papers, dissertations, conference papers, grants, and more (see content types & markup guides). (CrossRef Documentation Introduction to Posted Content)
Where and how should CrossRef DOIs be entered in the schemas schema.org, DataCite, ISO19XX and DCAT?
Overview of Crossref DOIs in schema.org, DataCite, ISO 19115/-3, and DCAT, each with short, runnable example snippets.
General rule everywhere: enter the DOI as a full HTTPS URI (https://doi.org/...). (CrossRef Display Guidelines)
schema.org (JSON-LD)
Where?
· For a publication: as @id (recommended) and/or identifier on the ScholarlyArticle.
· For references from datasets to publications: via citation (CreativeWork) with the DOI as identifier. (Schema.org ScholarlyArticle, science-on-schema.org GitHub)
Publication (has its own Crossref DOI):
{ "@context": "https://schema.org", "@type": "ScholarlyArticle", "@id": "https://doi.org/10.1234/example.5678", "name": "Example article title", "identifier": "https://doi.org/10.1234/example.5678"}Dataset refers to publication (Crossref DOI):
{ "@context": "https://schema.org", "@type": "Dataset", "name": "Example dataset", "citation": { "@type": "ScholarlyArticle", "@id": "https://doi.org/10.1234/example.5678", "identifier": "https://doi.org/10.1234/example.5678" }}(The types/properties are documented in schema.org; the Science-on-Schema guides show DOI best practices.) (schema.org ScholarlyArticle, science-on-schema.org GitHub)
DataCite (Schema 4.5)
Where?
· The dataset describes itself: its own DOI appears in identifiers (set by the repository).
· Reference to a publication with a Crossref DOI: relatedIdentifiers[] with relationType (e.g., IsReferencedBy, IsCitedBy, References, Cites) and relatedIdentifierType="DOI".
· Richer linkage: relatedItems[] (since 4.4/4.5) allows bibliographic details. (DataCite Metadata Schema, DataCite Introduction to the Metadata Schema)
Simple (relatedIdentifiers):
{ "relatedIdentifiers": [{ "relatedIdentifier": "https://doi.org/10.1234/example.5678", "relatedIdentifierType": "DOI", "relationType": "IsReferencedBy", "resourceTypeGeneral": "Text" }]}Detailed (relatedItems, 4.5):
{ "relatedItems": [{ "relationType": "IsReferencedBy", "relatedItemType": "JournalArticle", "relatedItemIdentifier": { "relatedItemIdentifier": "https://doi.org/10.1234/example.5678", "relatedItemIdentifierType": "DOI" }, "titles": [{ "title": "Example article title" }], "publicationYear": 2024 }]}(See DataCite Schema 4.5 including examples.) (DataCite Metadata Schema)
ISO 19115-1 / 19115-3 (XML)
Where?
· DOI as an identifier in CI_Citation: …/citation/cit:CI_Citation/cit:identifier/mcc:MD_Identifier/mcc:code = DOI URI, optionally codeSpace=https://doi.org.
· For references to publications, add a second CI_Citation under mri:associatedResource, or more simply under mri:MD_DataIdentification/mri:citation/cit:CI_Citation/cit:otherCitationDetails / cit:identifier. (Both patterns are common; identifier is cleanly machine-readable.) (ESIP ISO Citations, GitHub)
Resource citation with DOI (19115-3 namespaces):
<mdb:MD_Metadata xmlns:mdb="https://schemas.isotc211.org/19115/-3/mdb/2.0" xmlns:mri="https://schemas.isotc211.org/19115/-3/mri/2.0" xmlns:cit="https://schemas.isotc211.org/19115/-3/cit/2.0" xmlns:mcc="https://schemas.isotc211.org/19115/-3/mcc/1.0" xmlns:gco="https://schemas.isotc211.org/19103/-/gco/1.0"> <mdb:identificationInfo> <mri:MD_DataIdentification> <mri:citation> <cit:CI_Citation> <cit:title><gco:CharacterString>Example dataset</gco:CharacterString></cit:title> <cit:identifier> <mcc:MD_Identifier> <mcc:code><gco:CharacterString>https://doi.org/10.9999/dataset.1234</gco:CharacterString></mcc:code> <mcc:codeSpace><gco:CharacterString>https://doi.org</gco:CharacterString></mcc:codeSpace> </mcc:MD_Identifier> </cit:identifier> </cit:CI_Citation> </mri:citation> <!-- Reference to publication with Crossref DOI --> <mri:additionalDocumentation> <cit:CI_Citation> <cit:title><gco:CharacterString>Example article title</gco:CharacterString></cit:title> <cit:identifier> <mcc:MD_Identifier> <mcc:code><gco:CharacterString>https://doi.org/10.1234/example.5678</gco:CharacterString></mcc:code> <mcc:codeSpace><gco:CharacterString>https://doi.org</gco:CharacterString></mcc:codeSpace> </mcc:MD_Identifier> </cit:identifier> </cit:CI_Citation> </mri:additionalDocumentation> </mri:MD_DataIdentification> </mdb:identificationInfo></mdb:MD_Metadata>(ISO guides on CI_Citation and example XML show exactly this placement.) (ESIP ISO Citations, NASA Common Metadata Repository)
DCAT / DCAT-AP (RDF/Turtle)
Where?
· The identifier of a document (publication): as dct:identifier (literal) or as a resource with the DOI URI (recommended).
· Reference from the dataset to a publication: dct:isReferencedBy (dataset is referenced in the publication) or dct:references (dataset references the publication). For structured identifiers additionally adms:identifier. (DCAT, DCAT Application Profile Implementation Guidelines)
Dataset ↔ Publication (Crossref DOI as a resource):
@prefix dcat: <http://www.w3.org/ns/dcat#> .@prefix dct: <http://purl.org/dc/terms/> .@prefix schema: <https://schema.org/> .@prefix adms: <http://www.w3.org/ns/adms#> . <https://example.org/dataset/123> a dcat:Dataset ; dct:title "Example dataset" ; dct:isReferencedBy <https://doi.org/10.1234/example.5678> . <https://doi.org/10.1234/example.5678> a schema:ScholarlyArticle ; dct:title "Example article title" ; dct:identifier "https://doi.org/10.1234/example.5678" ; adms:identifier [ a adms:Identifier ; dct:issued "2024-06-01" ] .(W3C DCAT specifies identifier usage; DCAT-AP explains dct:identifier vs. adms:identifier.) (DCAT, DCAT Application Profile Implementation Guidelines)
Quick notes
· Always use https://doi.org/... (not doi:/dx.doi.org). (CrossRef Display Guidelines)
· In DataCite, for publication references prefer relatedIdentifiers/relatedItems with the correct relationType. (DataCite Metadata Schema)
· In ISO, store DOIs as an identifier in CI_Citation; additional online links are optional. (ESIP ISO Citations)