National Bibliography Number
National Bibliography Number (NBN), a group of publication identifier systems used by national libraries in certain countries like Germany, Italy, Finland, Norway, and Sweden. There is no global standard for the contents of NBNs; instead, they have a country-specific format. NBNs are typically used for documents which do not have a publisher-assigned identifier (like ISBN). They can be used to persistently identify media that are archived in national libraries, for instance PhD theses.
An NBN in Germany (
), in Bavaria (
= Bibliotheksverbund Bayern), library number 19 (University Library Munich), pointing to a PhD thesis on heat detection in cattle.