When using a group catalogue, for example https://picarta.on.worldcat.org/, to initiate ILL requests, WorldShare ILL automatically selects an OCN for records where this isn't supplied in the requested item. This is the case for most articles, which aren't cataloged on article level but on journal level. Only the journal has an OCN. In such cases, the system will match the article to a journal based on the ISSN. The matched OCN will be the one with the most holdings. If that isn't the OCN you expected or wished, for example because you want to send your request to libraries from your own country, you will have to change the OCN:
If you are a Dutch library using https://picarta.on.worldcat.org and wish to receive a more elaborate manual, please contact OCLC Support.