Persistent identifiers

A Persistent Identifier (PID) is a unique code consisting of a string of letters and numbers used to identify objects, people, or concepts. Examples include Digital Object Identifiers (DOIs) and International Standard Book Numbers (ISBNs). Researchers can also have a persistent identifier, such as an Open Researcher and Contributor ID (ORCID).


DOIs are persistent unique digital identifiers assigned to objects, such as research outputs like publications or datasets. A DOI is permanent and cannot be removed, but you can remove the public right to access the resource.

  • A DOI provides a persistent link to your work, even if its location on the internet changes over time. This helps others to locate and cite your work.
  • Digital tools like Altmetric Explorer use DOIs and other persistent identifiers to track research outputs and see how often they have been accessed, cited, or discussed.
  • You can use a DOI to manage your work in various scholarly systems (e.g. populating your ORCID profile and importing your record into the ARC’s Research Data Management System).
  • DOIs are exclusively issued by registered agencies, and you need to comply with the agency’s requirements to get a DOI for your work. It is not possible to self-register a DOI for an item made available only on your own website.
  • The Australian Research Data Commons (ARDC) is able to mint DOIs for Australian research data.
  • Publishers often assign a DOI to books, scholarly articles and datasets when they are published and made available electronically.

Getting a DOI

The University of Sydney Library can provide DOIs for some non-published materials.

Some other repositories can also provide DOIs, including:

  • Zenodo - An open repository with free uploads up to 50GB. All uploaded work is eligible for a DOI.
  • Figshare - An open repository with free uploads up to 5GB. All uploaded work is eligible for a DOI.
  • F1000 Research - An open research publishing platform for researchers in all subject areas. All uploaded slides and posters are eligible for a DOI.
  • Open Science Framework - A free open platform for research collaboration and sharing. Public research is eligible for a DOI.
  • ResearchGate - An open source of free scholarly articles. DOIs can be generated for eligible uploads.
  • LabArchives eNotebooks - An Electronic Laboratory Notebook (ELN) for safely storing research data. If you use a LabArchives eNotebook, you can make it available to the public by creating a DOI through the LabArchives system. 


ISBNs are persistent identifiers for books. They are used internationally across the book trade and library sector.


  • is internationally applied and recognised
  • is required by most retailers
  • improves the likelihood your book will be found and purchased
  • links to essential information about your book
  • enables more efficient marketing and distribution of your book
  • helps you collect and analyse book sales data.

An ISBN is not mandatory and does not provide copyright on a work. Publishers purchase or receive ISBNs from an affiliate of the International ISBN Agency.

  • Contact

    For more information on DOIs please email

    For information about ISBNs, please contact Sydney University Press.