Bibliothekssigel - Bibliothekssigel

A library seal is a unique identifier for libraries and related institutions (e.g. archives and museums ). The seals are issued by central offices in many countries and are mainly used in association catalogs , for interlibrary loans and for data exchange. The international system for library sigla has been the International Standard Identifier for Libraries and Related Organizations (ISIL) according to ISO 15511 since 2003 .


ISIL and library sigils are increasingly used as the primary identifiers for libraries and related institutions. In the long term, the aim is to dispense with the Sigel and only use ISIL instead. ISIL are used, among other things, as MARC organization codes to identify institutions that act directly or indirectly as suppliers of MARC data . The German ISIL agency is also the issuing body for these codes in Germany. In addition to being clearly assigned in an international context, ISILs are also better suited for use as identifiers in Internet applications and other software systems. For example, the ekz Reutlingen uses ISIL as an identifier for data coding on RFID-Crisps. In order to be able to use ISIL as an identifier in the context of the Semantic Web , the info: isil namespace was applied for so that each ISIL can be formulated as a Uniform Resource Identifier (URI) at the same time .


Index for the resolution of ownership abbreviations from 1914 [1]
First index with addresses from 1929 [2]

Originally, library sigils were awarded at the beginning of the 20th century as part of the work on the Prussian general catalog (" Althoff system "). The system was administered under the aegis of the “Information Office of the German Libraries” at what was then the Royal Library, later the Prussian State Library, and further developed for interlibrary loan and complete journal directories.

In 2003, the ISIL system was adopted as the international standard ISO 15511. ISIL stands for "International Standard Identifier for Libraries and Related Organizations" ("International Standard Identifier for Libraries and Related Organizations"). The ISIL as an internationally unique identifier is intended to simplify cross-border library services and the exchange of data. All existing library sigla are mapped to the new ISIL.


In Germany, the German ISIL agency and seal office at the Berlin State Library awards library seals and ISIL for institutions in Germany. In addition to the ISIL and code directory online, it published a printed code directory every two years until 2009. [3] The national ISIL center of the Swiss National Library is responsible for issuing the seal for Switzerland . In Austria, the conversion of the standards A 2657 and A 2656, according to which library seals ("ÖZDB-Sigel") and machine-readable identification ("BIK") are issued, to ISIL is being carried out by the Austrian Library Association . [4]The label offices or ISIL agencies in the individual countries are registered with the ISIL Registration Authority, which is based at the Danish Agency for Libraries and Media in Copenhagen. In addition to the national ISIL agencies, there are currently three agencies that can award ISIL regardless of national affiliation: OCLC operates its own international library directory with WorldCat Registry and integrates its identifiers with the prefix OCLC into the ISIL system. The journal database assigns ISIL with the prefix ZDB for virtual collections of electronic publications (also known as “product labels”), among other things within the framework of national licensesand for foreign libraries participating in the ZDB, for which no national ISIL has yet been assigned. The Library of Congress can also assign ISIL to libraries outside the USA with the prefix M.



According to ISO 15511, an ISIL consists of three parts:

  1. A country prefix according to ISO 3166-1 consisting of two letters or a non-country prefix consisting of 1, 3 or 4 letters. Only A to Z characters are allowed. The prefixes are assigned to the local ISIL agencies by the ISIL Registration Authority.
  2. A hyphen minus ( - , ASCII code 45)
  3. The local institution code , assigned by the respective ISIL agency. The letters A to Z and a to z, the digits 0 to 9 and the special characters hyphen-minus ( - ), slash ( / , ASCII code 47) and colon ( : , ASCII code 58) are permitted as characters. The library ID can contain a maximum of 11 characters.

The total length of an ISIL is limited to 16 characters. ISIL agencies can further restrict the possible characters for their namespace or specify a substructure so that already existing marking systems can be partially adopted. If the substructure reflects a geographical breakdown, the standard recommends using codes from ISO 3166-2 . The ISIL agencies are free to use upper and lower case in the library identifier; the assigned identifiers must, however, be unique even without this distinction. To represent an ISIL as a Uniform Resource Identifier (URI), the namespace isil in the Info-URI namespace ( RFC 4452) requested.

Examples of ISIL
ISIL ( URI ) ISIL agency Library
info: isil / DE-1 Germany Berlin State Library
info: isil / DE-Tue120 German-American Institute, Tübingen
info: isil / DE-7-022 Library of the Geographical Institute of the University of Göttingen
info: isil / DE-mus- 6 Digits Common ISIL mark of the museums
info:isil/CH-001025-1 Switzerland Library of the Swiss section of Amnesty International, Bern
info:isil/AU-TS:RL Australia CSIRO Forestry and Forest Products, Tasmanien
info:isil/GB-XY/N-1 Great Britain British Library Document Supply Centre Wetherby, West Yorkshire
info:isil/OCLC-BRI OCLC
info:isil/ZDB-1-OJD Journal database Oxford Journals Digital Archive (Nationallizenz)

German library seal

Based on a numbering of the Prussian libraries, various forms of library sigla developed: [5]

  • Number Sigel consist of numbers that have been enhanced in some cases by annexes letters to identify major department libraries.
  • Place symbols consist of a prefixed place code made up of letters and a number followed by a space. Combinations with letters are also possible after this.
  • Signs for institute libraries consist of the sign of the main library and, separated by a slash, an identifier of the institute library (usually as a number). These seals are no longer issued by the seal office, but directly by the responsible university or college library.

While these forms served their purpose well for everyday library work, their use as identifiers in databases is problematic, since the structure of a library sigla is not as formally defined as that of an ISIL and special characters such as spaces, slashes and umlauts are possible. There is a heuristic for mapping a sign to an ISIL ; to be on the safe side, however, it is better to look up the list of codes, as deviations are possible in individual cases.

Examples of German library seals
Sigel Type Library
1 Number seal Berlin State Library
5 N Number seal University and State Library Bonn, Department Library Medicine, Natural Sciences and Agriculture
B 451 Ortssigel US-Botschaft, Public Affairs / Information Resource Center
T 120 Ortssigel German-American Institute, Tübingen
7/039 Institutssigel University of Göttingen, Center for Surgery, General Surgery Department Library
Gö 39 a (outdated)
188/144 Institutssigel FU Berlin, Library of the John F. Kennedy Institute for North American Studies


  • Andreas M. Heise: Comments on indexes and library seals on the occasion of the 100th birthday of the former information office of the German libraries. In: Journal for Libraries and Bibliography (ZfBB). Volume 51, No. 5/6, 2004, ISSN 0044-2380 , pp. 305-315 (also as PDF ).
  • ISO: Information and documentation – International Standard Identifier for Libraries and Related Organizations (ISIL). ISO 15511:2003
  • Index of seals for the libraries of the Federal Republic of Germany . 16th edition. De Gruyter, Berlin et al. 2009, ISBN 978-3-598-23471-2 ( ISSN 0940-6921 ) [6] ( digitized version )


Individual evidence

  1. Information Office of the German Libraries (Ed.): Complete journal directory. Berlin: Royal Library, 1914, pp. XIV-XVII.
  2. ^ Information bureau of the German libraries (ed.): Complete directory of foreign journals (GAZ): 1914–1924. Berlin: Prussian State Library, 1929, pp. XI – XXXII.
  3. ↑ The printed index of symbols has been discontinued. Berlin State Library, May 30, 2011, accessed on September 18, 2020 .
  4. ISIL Registration Authority (Memento des Originals vom 4. August 2014 im Internet Archive) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.@1@2Template: Webachiv / IABot /
  5. Allocation of library tags . ( Memento from March 28, 2010 in the Internet Archive ) as of October 23, 2006.
  6. German ISIL agency and seal office at the Berlin State Library. Retrieved September 18, 2020 .