What is the ISSN-L?

If a publication appears in different formats with the same title (printed, online publication, CD-ROM), separate ISSN have to be assigned.

The ISSN-L (ISSN linking) is the superordinate identifier that applies to all the formats of this one title. It is assigned automatically by the International ISSN Centre. The ISSN-L makes is easier to manage different formats of the same publication.

Example:

“Aktuelle Rheumatologie”