Publications Office of the EU
Identifiers - Publications Office Web Guide
Identifiers v2


Last updated: 20/02/2024


If your publication is meant for the public, it is your responsibility to request international identifiers from the Publications Office (see Article 4(3) of Decision 2009/496/EC). This will ensure that your publication is internationally recognised as belonging to an institution/agency/body of the European Union. Your publication will also be included in the EU Publications online catalogue and preserved in an electronic archive.

Identifiers are alphanumeric strings which uniquely identify a given resource. They are linked to associated metadata (i.e. information describing that resource) and as such can be used to identify different formats, language versions, key titles of serials, etc.

Types of identifiers

Several types of publications receive different identifiers, as follows.

  • A catalogue number.
    This is the Publications Office’s own identifier, used for all publications produced or identified by the Publications Office.
  • An international standard book number (ISBN).
    This is primarily assigned to monographs (i.e. stand-alone publications).
  • An international standard serial number (ISSN).
    This is used for the identification of serial publications and ongoing integrating resources including websites (only under certain conditions)
  • A digital object identifier (DOI).
    This is a permanent digital identifier that provides a stable link to the resource.

Learn more about identifiers (EU login required).

How to request (and receive) identifiers

You can request identifiers by using the External link: UPP Author portal (EU login required); however, you will first have to submit a External link: request for accesss (EU login required).

Once access is granted, you will be able to log in with your EU Login credentials and create a new request. Select the bundle of services that best matches your needs, from ‘Identification services’ only and other ‘Stand-alone services’ to the full ‘Publication production services’ or specific ‘Multimedia/mobile apps’.

The service bundles will guide you to select the one that suits your needs; they will provide details about your publication and which services are included in each option.

Learn more about the UPP Author portal

If you need more details on the legal document identifiers, please contact the EUR-Lex helpdesk (

How to display the identifiers

Please consult the Interinstitutional Style Guide for relevant advice on how to display the different identifiers you receive following the internationally accepted rules and conventions.