Persistent identifier management at the Deutsche Nationalbibliothek (German National Library)

...frequently asked questions...


General information

  1. Who can I ask if I need more information?
  2. What other practical experiences are there regarding allocation, administration and registration of Persistent Identifiers?
  3. What are the advantages of Persistent Identifiers?
  4. To what objects are the URNs administered at the German National Library assigned?
  5. How is a URN structured?
  6. What is the structure of the URNs administered at the German National Library?
  7. Where can I get information to test the application of URNs?
  8. Can URNs be entered directly into a browser's address line?

URNs for online thesis and dissertations

  1. What is the procedure for assigning URNs for online thesis and dissertations?
  2. What steps are required to register URNs at the German National Library?
  3. How quickly are URNs for online thesis and dissertations registered at the German National Library?
  4. How can URNs for online thesis and dissertations be retrospectively assigned?

URNs for networked publications

  1. What is the procedure for assigning URNs for networked publications?
  2. How are URNs for networked publications structured?
  3. How are URNs for networked publications reported to the German National Library?
  4. How long does the registration procedure for URNs for networked publications take?

URNs for the entire document server

  1. What points must be noted in order to allocate URNs for an entire document server?
  2. What steps are required to allocate URNs for an entire document server?
  3. How are URNs for an entire document server reported to the German National Library?

Questions about practical use

  1. What happens if URNs are inadvertently assigned in duplet?
  2. What transfer methods are there for registering URNs at the German National Library?
  3. How is the last part of a URN, the "NISS", structured?
  4. How is the URN check digit created?
  5. How are URLs updated if they are subsequently changed?
  6. How can stable links be created in an online catalogue?
  7. How are URNs captured in bibliographic descriptions and how are they delivered via other data services from the German National Library?
  8. How are DOIs handled?

General information

1.Who can I ask if I need more information?

The responsible persons at the German National Library can be contacted via the following e-mail address for all organisational, technical and content related questions: nbn-request@d-nb.de

2.What other practical experiences are there regarding allocation, administration and registration of Persistent Identifiers?

The discussion list nbn-ub@d-nb.de provides a forum for the exchange of information and experiences with other institutions using Persistent Identifiers. At the same time this is intended to facilitate a discussion of this subject on a theoretical level. Please find information on subscribing in the Mailing list.

3.What are the advantages of Persistent Identifiers?

Persistent Identifiers can replace URLs in catalogues or other reference systems or they can be used as stable references in documents themselves. The maintenance involved in updating references is thereby reduced. Digital publications have globally unique identifiers, with which they can be more reliably cited.

4.To what can URNs administered at the German National Library assigned?

URNs from the namespace "nbn:de" are currently assigned for the following types of document:

  • Online thesis and dissertations
  • Networked publications archived at the German National Library such as research reports, articles, online serial publications (series R and M in the German National Bibliography), publications from publishing houses,
  • Networked publications which have not yet been archived at the German National Library such as research reports, serial type publications published online, videos, conference proceedings, research papers, reports
  • Networked publications administered on certified document servers, such as periodical articles, dissertations, festschrifts, essays
General information can be found in the URN strategy of the German National Library.

5.How is a URN constructed?

URNs comprise several hierarchically constructed components. These are the namespace (Namespace, NID) which is itself composed of severalSubnamespaces, SNID, such as for example "URN:NID:SNID-NISS".

6.What is the structure of the URNs administered at the German National Library?

URNs administered at the German National Library have the following general structure:
urn:nbn:de:[designations of library association]:[official notation of university libraries]-[unique production number][check digit]
Example:
urn:nbn:de:gbv:089-3321752945

URNs are assigned with the following structure for libraries outside a library consortium:
urn:nbn:de:[four digit numeric code]-[unique number][check digit]
Example:
urn:nbn:de:1111-00016
"urn" shows the resolution routine, "nbn" indicates the "National Bibliography Number" (NBN) international namespace, a namespace which is co-operatively administered by national libraries. "de" stands for the sub-namespace "de", for which the German National Library is responsible. [designations of library association] is the acronym for the relevant library consortium, [official notation of university libraries] is the library symbol for the library in question, or a four digit code for institutions not part of a library consortium. [unique producation number] must be a unique production number. The [check digit] is used to validate the complete URN alpha-numeric string.

7.Where can I get information to test the application of URNs?

  • the German National Library's resolving mechanism Demonstration page features a web-based form for resolving URNs.
  • A search function exists at OASE - Open Access to Scientific Literature Online (the Karlsruhe Virtual Fulltext Catalogue).
  • URNs can be entered directly into the address line using the Browser plugin for Mozilla.

8.Can URNs be entered directly into a browser's address line?

URNs for thesis and dissertations

9.What is the procedure for allocating URNs for online thesis and dissertations?

If you are already registered to report online thesis and dissertations at the German National Library, then you are simultaneously registered for the URN procedure as well. You will then receive a URN sub-namespace, starting with "urn:nbn:de" from the German National Library. For this please contact the responsible persons at the German National Library via e-mail nbn-request@d-nb.de. This will mean you can allocate URNs and report them to the German National Library. You can find introductory information on this by consulting Uniform Resource Name (URN) administration and organisation for university libraries.

10.What steps are required to register URNs at the German National Library?

The established registration process for online thesis and dissertations has been extended to cover the initial registration of URNs. This means that URNs can be registered at the German National Library via the existing transfer interfaces , along with metadata in METADISS format This specifically affects the following points:

  • Internal workflow for allocating the last component of a URN, the "NISS"
  • Calculating the URN's check digit
  • Extending the "METADISS" metadata format, as of 2005 "XMetaDiss"
  • Reporting URL changes and administrative details such as contact people to the German National Library.

More detailed information can be found at FAQ document "Archiving online academic publications at the German National Library" and under the point "Deutsche Nationalbibliothek".

11.How long does it take to register a URN?

The German National Library first processes the online thesis and dissertations and then registers the URNs with a delay of 1 to 2 hours.

12.How can URNs for online thesis and dissertations be retrospectively assigned?

A web form can be used for subsequent registration of dissertations which are already archived at the German National Library. This form is available in the restricted access area.

In the case of large scale multiple registrations, interested parties will be sent a file containing all the information required (IDN and URL of the university library) in a fixed format. URNs assigned subsequently must be added to these details. The file is then sent back to the German National Library. A comparison is then made with the catalogue of the German National Library every six months (in June and December) so that additional work is minimised. If you are interested in this you can contact the responsible persons via e-mail nbn-request@d-nb.de. You will then receive detailed information and examples.

For users of OPUS there is script available to automatically generate URNs retrospectively and to capture this information in OPUS. This is located on the internal OPUS software site, ready to be downloaded.

URNs for networked publications

13.What is the procedure for allocating URNs for networked publications?

If you are registered to report networked publications to the German National Library, then you are simultaneously also registered to process URNs. You will use the same verification details. You will then receive a URN sub-namespace. The relevant staff member within the German National Library will allocate this. You can contact the responsible person at nbn-request@d-nb.de. The next step is to allocate a complete URN and to register the networked publication using the interactive registration form at the German National Library. The URN will then be automatically registered.

14.How are URNs structured?

URNs are structured in accordance with guidelines in the URN strategy at the German National Library.

15.How are URNs for networked publications reported to the German National Library?

An interactive registration form is available for networked publications that have already been registered at the German National Library. There you can enter the URN and the associated URL.

Detailed instructions and further links are located at URN transfer interfaces.

16.How quickly are URNs for networked publications registered?

URNs for networked publications are slightly delayed (up to a maximum of two hours) after the catalogue record has been created.

URNs for the entire document server

17.What points must be noted in order to allocate URNs for an entire document server?

URN assignment is linked to requirements such as secure archiving, aspects of long-term archiving and the requirement to update URLs. These can be consulted in the URN strategy at the German National Library. Criteria for authorised document servers are taken from the DINI Certification. If an institution meets these conditions, then a URN sub-namespace will be allocated by the German National Library. If these conditions are not adhered to, then the resolver's error messages will be referred to the institution responsible for the URN sub-namespace.

18.What steps are required to assign URNs for an entire document server?

  • Please check that all the requirements in the URN strategy at the German National Library have been met.
  • Do you meet the DINI certification criteria for document servers?
  • In order to receive a URN sub-namespace, please contact the responsible persons at the German National Library: nbn-request@d-nb.de.
  • In order to assign URNs to all the objects on a document server, you will need an allocation algorithm. For this, please contact the responsible persons at the German National Library.
  • The URNs must be registered at the German National Library within 24 hours of their publication on a document server.
  • If objects' URLs change, then these must be reported to the German National Library.

19.How are URNs for an entire document server reported to the German National Library?

  • Using a Web front end URNs can be manually administered.
  • active registration process:
    All relevant registration processes can be automated by sending an XML record as an attachment to an e-mail to the German National Library.
  • passive registration process using OAI 2.0
    After implementing "xepicur" in a data provider's OAI 2.0, all relevant data resulting from the URN management process will be selectively harvested once daily by the German National Library.

Comprehensive transfer interface details can be found at Service.

Questions about practical use

20.What happens if duplicate URNs are accidentally allocated?

The German National Library performs a check for duplicate entires before a URN is registered. If an error message is generated, then the URN will not be registered. The institution concerned will be notified.

21.What transfer methods are there for registering URNs at the German National Library?

The German National Library is able to receive data created as part of the URN management process in various ways. You can then choose whichever method can best be integrated into your institution's existing workflow.

  • existing procedures for registering online resources and archiving at the German National Library.
  • active reporting process via e-mail.
  • passive reporting process via OAI 2.0

22.How is the last part of a URN, the "NISS", formed?

The NISS element can consist of a running number, a unique production number or a combination of a date and a running number. Alpha-numeric acronyms are also possible. No set number of characaters needs to be specified as this can be expanded as necessary.

Practical examples:

urn:nbn:de:1111-20040330226
urn:nbn:de:bsz:93-opus-10178
urn:nbn:de:gbv:089-2414302835
urn:nbn:de:0001-00174
urn:nbn:de:0002-0228
urn:nbn:de:0003-0027
urn:nbn:de:bsz:16-opus-11023
urn:nbn:de:bvb:19-10333
urn:nbn:de:gbv:18-10183
urn:nbn:de:hbz:294-10166
urn:nbn:de:hebis:30-0000000210
urn:nbn:de:kobv:517-0000218
urn:nbn:de:swb:ch1-199900539

23.How is the URN check digit created?

The URN check digit refers to the "urn:nbn:de:[...]" character string and is added immediately following the last character of the URN. The aim of this is to validate the character string.

The URN check digit can be calculated using a web form. A Perl script can also be supplied on request which will calculate check digits automatically.

You will find a verbal desrciption of the check digit algorithm here.

24.How are URNs updated if they are subsequently changed?

25.How can stable links be created in an online catalogue?

The URN can be displayed as a clickable link in an online catalogue as follows:
The string urn:nbn:de:gbv:089-3321752945 points as a hyperlink to the URL representation of the URN:
http://nbn-resolving.de/urn/resolver.pl?urn=urn:nbn:de:gbv:089-3321752945

26.How are URNs captured in bibliographic descriptions and how are they delivered via other data services of the German National Library?

From 1 August 2004, Persistent Identifiers will be tranferred to MAB as follows:
552 "Persistent Identifiers (PI)"

  • Indicator:
    • blank = not specified
    • a = Digital Object Identifier (DOI)
    • b = Uniform Resource Name (URN)
    • c = Handle

(see MAB documentation)
Field 655 $g does not apply

URNs will currently be indexed in the form "urn:nbn:de:gbv:089-3321752945" in series H (Online thesis and dissertations) and series A (Publications from publishing houses) of the German National Bibliography.

URNs are available via the Z39.50 Gateway. In the Online catalogue of the German National Library individual URNs can be searched using the "Standard number" category.

27.How are DOIs handled?

Whenever networked publications with DOIs are registered at the German National Library, then the DOI can be captured in MAB field 552 of the bibliographic description (see MAB documentation) and thus be supplied via bibliographic data services.



02.01.2008