For decades the MARC standards (Machine Readable Cataloguing) forms the basis for cataloguing in the library. Through the years, MARC is adjusted to developments in the field, so that by now much more than traditional library material can be processed. Although MARC21 is not always immediately apparent, it is used ‘under water’ in most catalogue applications. MARC is of great importance for the digital exchange of information. It is widely used as the standard exchange format for bibliographic data. As…