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Citation Guide


"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.

We recommend that when DOIs are available, you include them for both print and electronic sources. The DOI is typically located on the first page of the electronic journal article, near the copyright notice. The DOI can also be found on the database landing page for the article.

For more on DOIs, see Electronic Sources and Locator Information (PDF) and the DOI category of the APA Style Blog."

Note: the DOI can be found on the first page of the article, the footer, the record page, or the publisher's website

If you can not find the DOI on none of the mentioned locations, check the following websites:

 Retrieved from

Permanent Link

For online sources without DOIs, it is extremely important to make sure the URL used to point back to the source is not a search string or a proxy link. It is usually best to go to the publisher's home site if you are unsure whether the link you used to access the source is the permanent link for the source.  

To have more information about Permanent Link, go to this page: