Koc University Institutional Repository

A digital object identifier (DOI) is a unique alphanumeric string assigned by a registration agency (the International DOI Foundation) to identify content and provide a persistent link to its location on the Internet. The publisher assigns a DOI when your article is published and made available electronically.

All DOI numbers begin with a 10 and contain a prefix and a suffix separated by a slash. The prefix is a unique number of four or more digits assigned to organizations; the suffix is assigned by the publisher and was designed to be flexible with publisher identification standards.

For detailed information: http://www.doi.org/ 

You must use a service offered by a DOI Registration Agency (RA). RAs collect metadata, assign DOI names, and offer other services such as reference linking or metadata lookup. See the list of RAs, and contact the ones whose services best meet your needs. If you do not see an appropriate application listed, consider approaching an existing RA or developing a community to build the service you require (see the DOI Handbook, 8 Registration Agencies, for more information). You do not need to be a member of the International DOI Foundation in order to work with an RA.

The DOI system does not provide a central search capability across all DOI names, but most web search engines will show DOI names in the results of a search by title, by name, or by topic or related terms. The reverse will also work; enter a DOI name and the search engine will show you what item that DOI was assigned to. However, this sort of query facility may also be offered by Registration Agencies or other services for DOI names in one defined area, as a value-added feature. These may be a paid for service or free to all users. For an example, see Crossref free DOI lookup.

The cost of registering new DOI names depends on the services you purchase. Contact a DOI Registration Agency to discuss your options. Each RA is different, and each is free to offer its own business model. For an example of the costs of a DOI service for publishers, see the Crossref publisher fees. The IDF does not determine the costs charged to end users. Existing DOI names can be resolved by users free of charge.