Assign the following published IDs to mandatory publications: ISBN (International Standard Book Number), ISSN (International Standard Number for Series and Other Periodicals), and DOI (Digital Object Identifier). The purpose of these international identifiers is to provide publications with a unique and exclusive mark valid throughout the world.

DOI (DIGITAL OBJECT IDENTIFIER)

DOI is a string used to uniquely identify electronic documents.

The DOI is requested and registered in a central database through agencies, the ELTE University Library is in contact with the CrossRef agency.

DOIs can also be requested for monographs, study and conference volumes, and journals.

The DOI consists of a prefix followed by a suffix. In possession of the prefix received from the University Library, the editorial offices themselves form the DOI-s, for which we can provide recommendations and assistance. For journals that use OJS (Open Journal System), the generation and placement of the DOI can also be automated.

Conditions for DOI registration:

- The cross-linking obligation is to indicate the DOI of the documents in the bibliography of the publication.

- Ensuring long-term accessibility, according to which the document must be archived in the Digital Institutional Knowledge Base (EDIT) of ELTE in good quality.

- A unique URL to the document is also required to request a DOI. In the absence of a website, repository storage per article may be a good alternative.

- The DOI must be included in all versions of the documents (including both electronic and hard copy).

ISBN (INTERNATIONAL STANDARD BOOK NUMBER)

An ISBN is a numeric code that uniquely identifies books, audiobooks, electronic books, monographic CD-ROMs, maps.

The ISBN can be requested at the ISBN office of the National Széchényi Library.

ISSN (INTERNATIONAL STANDARD SERIAL NUMBER)

The ISSN is a numeric code that uniquely identifies periodicals as well as series.

The application for the ISSN is made at the Hungarian ISSN International Center in the National Széchényi Library.