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A window of a referrer is open on a wikipedia article using citation templates with embedded COinS tags An example of referrers acting on a wikipedia article using citation templates with embedded COinS tags

ContextObjects in Spans (COinS) is a method to embed bibliographic metadata in the HTML code of web pages. This allows bibliographic software to publish machine-readable bibliographic items and client reference management software to retrieve bibliographic metadata. The metadata can also be sent to an OpenURL resolver. This allows, for instance, searching for a copy of a book at a specific library.


In the late 1990s, OpenURL was created at Ghent University as a framework to provide context-sensitive links. The OpenURL link server implementation called SFX was sold to Ex Libris Group which marketed it to libraries, shaping the idea of a "link resolver". The OpenURL framework was later standardized as ANSI/NISO Z39.88 in 2004 (revised 2010). A core part of OpenURL was the concept of "ContextObjects" as metadata to describe referenced resources.

In late 2004, Richard Cameron, the creator of CiteULike, drew attention to the need for a standard way of embedding metadata in HTML pages. In January 2005, Daniel Chudnov suggested the use of OpenURL. Embedding OpenURL ContextObjects in HTML had been proposed before by Herbert Van de Sompel and Oren Beit-Arie and a working paper by Chudnov and Jeremy Frumkin. Discussion of the latter on the GPS-PCS mailing list resulted in a draft specification for embedding OpenURLs in HTML, which later became COinS. A ContextObject is embedded in an HTML span element.

The adoption of COinS was pushed by various publications and implementations. The specification was, which includes specific guides to implement COinS for journal articles and books.

Summary of the data model

From OpenURL 1.0 COinS borrows one of its serialization formats ("KEV") and some ContextObject metadata formats included in OpenURL implementation guidelines. The ContextObject implementation guidelines of COinS include four publication types (article with several subtypes, book, patent, and generic) and a couple of simple fields. However, the guidelines are not required part of COinS, so the standard does not provide a strict metadata model like Dublin Core or the Bibliographic Ontology.

Use in websites

The following websites make use of COinS:

Server-side applications

Some server-side applications embed COinS, including refbase.

Client tools

Client tools which can make use of COinS include:

See also


  1. ^ Chudnov, Daniel (2006-07-14). "COinS for the Link Trail". Library Journal: 8–10. Archived from the original on 2006-10-22.
  2. ^ ANSI/NISO Z39.88-2004(R2010) – The OpenURL Framework for Context-Sensitive Services. National Information Standards Organization. 2004. ISBN 978-1-880124-61-1. Archived from the original on 2013-10-02. Retrieved 2013-12-15.
  3. ^ Cameron, Richard (2004-12-20). "Autodiscovery and embedding metadata". gcs-pcs-list. Archived from the original on 2011-07-23. Retrieved 2011-03-20.
  4. ^ Chudnov, Daniel (2005-01-06). "sample inline openurl". gcs-pcs-list. Archived from the original on 2011-07-23. Retrieved 2011-03-20.
  5. ^ Van de Sompel, Herbert; Beit-Arie, Oren (July–August 2001). "Generalizing the OpenURL Framework beyond References to Scholarly Works – The Bison-Futé Model". D-Lib Magazine. 7 (7/8). doi:10.1045/july2001-vandesompel. ISSN 1082-9873.
  6. ^ Chudnov, Daniel; Frumkin, Jeremy (2004-12-10). "Service Autodiscovery for Rapid Information Movement". Archived from the original on 2004-12-15.
  7. ^ "gcs-pcs-list". Google Groups. Retrieved 2010-06-07.
  8. ^ Hellman, Eric (ed.). "Latent OpenURLs in HTML for Resource Autodiscovery, Localization and Personalization" (draft). Archived from the original on 2017-01-18. Retrieved 2011-03-20.
  9. ^ "OpenURL COinS: A Convention to Embed Bibliographic Metadata in HTML". Archived from the original on 2014-09-13. Retrieved 2014-09-24.
  10. ^ Apps, Ann (2003-04-16). "Z39.88-2004 KEV Implementation Guidelines". MIMAS, The University of Manchester, UK. Archived from the original on 2018-11-20. Retrieved 2011-03-20.
  11. ^ a b Reichelt, Jan (2009-08-05). "Mendeley Web now supports COinS". Mendeley Blog. Retrieved 2013-12-14.
  12. ^ "Wikipedia:COinS". Wikipedia. 2019-12-17.
  13. ^ "Standard link resolver support: OpenURL & COinS". refbase. Retrieved 2023-03-11.
  14. ^ "BibDesk Help: 5.10.5 Web Group". Retrieved 2023-03-11.
  15. ^ "Importing with the Hunter". Citavi Manual. Retrieved 2023-03-11.
  16. ^ "dev:exposing metadata:coins". Zotero Documentation. Retrieved 2023-03-11.

Further reading