Namespace Identifier: NBN This namespace ID was formally assigned to the National Bibliography Number in October 2001, when the namespace was registered officially [RFC3188]. Utilization of URN:NBNs had started in demo systems already in 1998. Since 2001, tens of millions of URN:NBNs have been assigned. The number of users of the namespace has grown in two ways: new national libraries have started using NBNs, and many national libraries using the system have formed new liaisons. Version: 5 Date: 2018-04-09 Registrant: National Library of Finland Role: URN Service Desk Email: kk-urn&helsinki.fi Postal: P.O. Box 15, 00014 University of Helsinki, Finland Web URL: http://www.nationallibrary.fi/ The National Library of Finland registered the namespace on behalf of the Conference of the European National Librarians (CENL) and Conference of Directors of National Libraries (CDNL). The NBN namespace is available for free for the national libraries. They can allow other organizations to assign URN:NBNs and use the resolution services established by the library for free or for a fee. The fees, if collected, can be based on, e.g., the maintenance costs of the system. Purpose: See Section 3 of RFC 8458 Syntax: See Section 4.2 of RFC 8458 Assignment: See Section 4.1 of RFC 8458 Security and Privacy: See Section 7 of RFC 8458 Interoperability: National libraries and their partners usually apply URN:NBNs if a standard identifier such as ISBN is not applicable for the resource to be identified. Some overlap with other URN namespaces is possible. URN:NBNs may contain characters which must be percent-encoded, but usually they consist of printable ASCII characters only. Resolution: See Section 4.4 of RFC 8458 Documentation: RFC 8458 Revision Information: This version of the URN:NBN namespace registration has been updated to use the revised definition of URN syntax from RFC 8141, although usage of r-components is not specified yet. In addition, non-ISO 3166 (country code) based NBNs have been deleted due to lack of deployment. The entire NBN prefix is now specified to be case insensitive in accordance with established practice. This version also includes numerous clarifications based on actual usage of URN:NBNs.