Resources published by publishers operating in multiple countries are generally identified by one and the same ISSN National Centre.
When a publisher has offices in many countries, there is a risk that several ISSN National Centres could identify its publications, which would then receive several ISSN.
This is contrary to ISSN’s fundamental rules: one and only one ISSN should be associated with a given publication.
To avoid duplicate ISSN assignments, the ISSN National Centres of the different countries the publisher operates in agree that only one of them shall assign the ISSN for all of this publisher’s publications.
Below are lists of the agreements established between ISSN National Centres for the registration of continuing resources published by multinational publishers.