The following materials provide high-level, introductory discussion about DOI^® names; detailed coverage of policy, operations and technology; and a description of the components of the DOI^® System and its underlying technology.

A factsheet summarizing the key elements of the DOI System, including its components, operation, governance and technical infrastructure.

An article on the DOI System by Norman Paskin, revised March 2009, for the (forthcoming, 2010) third edition of the Encyclopedia of Library and Information Sciences, Taylor & Francis Group. [PLEASE NOTE: The pre-publication proof provided here for information only is not paginated and not yet published; it should not be used for citation purposes.]

The Introductory Overview is a summary of the system, and basic introduction to the Handbook.

"Digital object identifier", entry in Wikipedia.

Overview of the DOI System slide presentation (PowerPoint Presentation). This presentation is available in an extended form as the Overview module of a multi-part workshop course on the DOI System.

Additional Illustrations: The Role of the DOI System as a Persistent Identifier (JPG); Multiple Resolution (JPG); and DOI Data Model: the Application Profile Framework (JPG).

The DOI^® System is currently being standardised through the International Standards Organisation, ISO. In April 2008 the Committee Draft prepared by an international Working Group was approved, after voting by ISO's national bodies, for distribution as a Draft International Standard (DIS). In February 2009, ISO provided further editorial comments on that draft. A further revised draft was submitted to ISO on 2 April 2009. Depending upon the result of ISO activities and further voting, the final standard may be published in 2009 or 2010.

For further information, please contact the convenor of the ISO Working Group: Norman Paskin (n.paskin@doi.org). See also the DOI System overview article, which incorporates material from the draft standard.

DOI is a registered URI within the info-URI namespace (IETF RFC 4452, the "info" URI Scheme for Information Assets with Identifiers in Public Namespaces). Further information is available at http://info-uri.info.

DOI names may be expressed as URLs through a proxy server. A URL is a URI that, "in addition to identifying a resource, [provides] a means of locating the resource by describing its primary access mechanism (e.g., its network 'location')." [Quoted from: Tim Berners-Lee, Roy T. Fielding, Larry Masinter, (January 2005), "Uniform Resource Identifier (URI): Generic Syntax", Internet Society, RFC 3986.]

The DOI System is an implementation of the Handle System. There are three Handle System RFCs:

DOI names use a semantic data dictionary and the IDF is the formal Registration Authority of the MPEG21 Rights Data dictionary. For further information on the RDD please send a request to contact@doi.org. For information on MPEG, see the MPEG website.

The DOI syntax is a NISO standard. See the DOI Handbook, Appendix 1, ANSI/NISO Z39.84-2000 Syntax for the Digital Object Identifier. The International DOI Foundation is a member of the National Information Standards Organization (NISO).

DOI names are an implementation of the CNRI Handle System^®, in which the term "DOI" is used instead of "handle" to describe the identifiers. For more information on the role of the Handle System in the DOI System, see the Factsheet "DOI System and Handle".

The Handle System web site includes an overview of the Handle System, definition of the namespace, and protocol specification which have been published as IETF Informational RFCs. Also of interest to the community is a discussion of Handle System scalability and an explanation of handle resolution. (See also the DOI^® Handbook, Chapter 3, Resolution.)

CNRI and ITU recently entered into an agreement to collaborate on use of the Handle System and the Digital Object Architecture (which Handle System is part of) more generally, and are working on the specific details of that collaboration. ITU has listed the Handle System as an "emerging trend": http://www.itu.int/osg/csd/emerging_trends/handle_system/index.html

DOI names use a semantic data dictionary, the indecs data dictionary, which is based on work including the original indecs project and its further development into the MPEG21 Rights Data dictionary. For more information on the role of the Data Dictionary in the DOI System, see the Factsheet "DOI System and data dictionaries".

View an IDF presentation on Persistent Identifier concepts and their development. (ZIP archive, PowerPoint presentation)