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DOIs: What they are and how to cite them

DOIs, or Digital Object Identifiers, are becoming increasingly common as publishers begin to assign them to journal articles. This guide will explain their purpose and how to include them in a bibliography.

What is a DOI?

Definition from
The Digital Object Identifier (DOI®) System is for identifying content objects in the digital environment. DOI® names are assigned to any entity for use on digital networks. They are used to provide current information, including where they (or information about them) can be found on the Internet. Information about a digital object may change over time, including where to find it, but its DOI name will not change.

The DOI System provides a framework for persistent identification, managing intellectual content, managing metadata, linking customers with content suppliers, facilitating electronic commerce, and enabling automated management of media. DOI names can be used for any form of management of any data, whether commercial or non-commercial.


What does that mean?

A digital object identifier (DOI) is a unique alphanumeric string that identifies content and provide a persistent link to its location on the Internet. The publisher assigns a DOI when the 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.

Not all articles or journals use DOIs; if you can't find a DOI you can use the persistant url in your citation instead.

DOI Examples

Here are some examples of DOIs:



A DOI is a permanent ID that, when appended to in the address bar of an Internet browser, will lead to the source.

For example, will take you directly to the information page for the article "An Analysis of the Pricing of Traits in the U.S. Corn Seed Market."

Creating Permalinks

If an article has not been assigned a DOI, many citation styles require that you create a permanent link so that other users can find and view the article.  For information on creating a permalink, visit our FAQ page for help.

What is a permanent link?

The URL (Uniform Resource Locator or Web address) appears in a Web browser's address box, when an online article is viewed, is usually intended to be temporary and often does not function a few days or weeks later. Links designated as "permanent", "persistent" or "stable" are designed specifically to remain active and useable over time.

Where Can I Find the DOI?

The location of the DOI can depend on many things. Here are some places to look for the DOI:

  • First page of the electronic journal article
  • Near the copyright notice
  • Database landing page for an article
  • Hidden behind a button
  • In the citation generated by the database
  • Online using the free DOI lookup on

finding a doi









Not every electronic journal article has a DOI. If no DOI is available and you retrieved the journal article online, you should include the persistent URL.