Persistent identifiers for publications and data

A unique and persistent identifier

A persistent identifier (PID) is a unique identifier that helps to distinguish one (or a series of) objects from others. The use of a PID makes it easier to reference and link to an object, such as a scholarly article or a dataset in a repository.

Different types of PID

There are several different forms of identifiers. DOI (digital object identifier) and URN (uniform resource number) are two common examples, which are used for both publications and research data. For publications, ISBN (international standard book numbers) and ISSN (international standard serial numbers) are also used. 

DOI (digital object identifier)

DOI is a unique persistent identifier assigned to a publication or a dataset to make the object findable in the long term. A DOI consists of letters and numbers, which are associated with a prefix to act as a link. The DOI link is persistent and does not change over time, regardless of a change of web address or storage location.

Scholarly publishers typically assign a DOI to their journal articles, which is usually found in the abstract or in the article itself. Some monographs and anthologies published in electronic format are also assigned a DOI. In these cases, chapters may have individual DOIs. Many data repositories, such as the Swedish National Data Service, Zenodo, and Figshare repositories, also use DOIs for data made available in the repository.

DOIs can be used to reference publications and data, for example, in a reference list. Always include the DOI when referencing material and ensure that the DOI of both the article and the dataset is visible in conjunction with other information used to reference your work.

Read more about DOI at the International DOI Foundation and the Swedish National Data Service (SND):

DOI (International DOI Foundation)

PID services (SND)

URN (uniform resource number)

Like the DOI, the URN is a persistent identifier assigned to digital resources to ensure that the resource is retrievable regardless of where it is currently located and stored. URNs are used for both publications and research data.

Publications registered in DiVA are automatically assigned a URN:NBN, where NBN stands for National Bibliography Number. All publications in DiVA thus have a persistent link, which you can find in the top right corner of each record.

Read more about URN:NBN on the National Library's website:

URN:NBN (National Library of Sweden, in Swedish)

ISBN (International standard book number)

ISBN is used as a unique identifier for books, reports, theses, and other similar publications. Revised versions and new issues or editions of the same publication are assigned new ISBNs.

Read more about ISBNs on the National Library's website and at the International ISBN Agency:

ISBN (National Library of Sweden, in Swedish)

What is an ISBN? (International ISBN Agency)

ISSN (International standard serial number)

ISSN is used to identify a series of publications, such as a journal and a report series. A book can have both an ISSN and an ISBN if it is part of a book series.

Read more about ISSN on the National Library's website and at the ISSN International Centre:

ISSN (National Library of Sweden, in Swedish)

What is an ISSN? (ISSN International Centre)

Meet the FAIR principles with an identifier

The FAIR principles aim to make publicly funded research results findable, accessible, interoperable with other systems, and reusable. In other words, both publications and research data should be easy to find and reuse. Many funders require your research data to meet FAIR criteria.

You can read more about FAIR data at the Swedish Research Council and FAIR for publications at the National Library:

Making research data accessible and FAIR criteria (Swedish Research Council)

The FAIR principles (National Library of Sweden, in Swedish)

Link a PID to your research data

Your research data should be searchable but also citable and traceable. This is done with the help of a PID, such as a DOI. When you share your data in a repository, such as the Swedish National Data Service (SND) catalogue, your data is provided with a DOI. Because PIDs follow predictable formats, they are machine-readable, meaning that PIDs can be used to link information without the need for a human to be active in the process.

To use PID in a way that meets the FAIR principles, you need to:

• asssign your data descriptions, data and related materials a PID;
• ensure that both the data description, its associated materials, and the PID are in machine-readable format;
• enter the PID in a metadata field when registering research data;
• ensure that your data descriptions always contain a PID link to the data material.

ISBN for publications published at Umeå University

You can order ISBN through the library if you have written a publication where Umeå University is the publisher. If the publication is published in both printed and digital format, each format is to have an ISBN of its own. ISSN for publication series, on the other hand, are administered by the faculty or department responsible for publishing, not the library.

Order ISBN

Identifiers are important for analysis

Persistent identifiers are useful in various bibliometric analyses, such as mapping scholarly publishing in different research fields. For instance, unique identifiers are used to trace how a publication or dataset is cited. It is also possible to see how a publication or dataset is mentioned in, for example, news sources and social media, known as altmetrics. 

You can read more about bibliometrics and altmetrics here:

Analysis and evaluation

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ORCID, Umu-id, and other identifiers for researchers

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