National Bibliography Number
National Bibliography Number (NBN) is a group of publication identifier systems used by national libraries in countries such as Germany, Italy, Finland, Norway, The Netherlands 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 such as an ISBN. They can be used to identify persistently media that are archived in national libraries, for instance Ph.D. theses.
An NBN in Germany (
de), in Bavaria (
bvb = Bibliotheksverbund Bayern), library number 19 (University Library Munich), pointing to a PhD thesis on heat detection in cattle.