Function of the ISSN

Each ISSN identifies a particular serial publication. The ISSN identification number is inseparably linked to the key title, a form of title standardized according to the rules of the ISSN international computer registration system. Because of this close link, if the key title changes due to a change in the title of the serial publication, the changed title must be identified with a new ISSN.

If the title or key title of the serial publication remains unchanged, while its place of publication, publisher or issuer, frequency of publication, or possibly its external format or internal content change, even with these changes, the same ISSN will continue to identify the publication.

Independent, periodically issued supplements, branches, sub-series, etc. have their own ISSN.

The different variant editions of a serial publication (variant editions in other languages, local or time variant editions, variant editions on differing media, e.g. cassette, microfiche, floppy disc, CD-ROM or appearing on the Internet) must be identified with a separate ISSN.

Once used, an ISSN cannot be used again in connection with another title!