Digital Object Identifier [DOI]

The DOI is a unique alphanumeric string assigned by a registration agency to identify content and provide a persistent link to its location on the Internet. When a DOI is available, you must include the DOI instead of the URL in the reference. Because the DOI string can be long, it is safest to copy and paste whenever possible. Provide the alphanumeric string for the DOI exactly as published in the article.

To illustrate, the reference noted below was retrieved from CINAHL Full-Text Database. As you can see, since the DOI is included, no database name or URL is necessary (because this is the final version of the article). The DOI serves as a unique identifier. Most publishers are moving toward including the DOI on the first page of the article, however, for now they are commonly found in the online database search report along with the abbreviated abstract (if available) as shown in the picture below. Once the DOI is set as an active link, the reader will be directed to and directed to the article or a link to purchase the article. Since DOI numbers are complex, APA suggests copying and pasting the DOI into the reference.



A DOI may be verified by searching the Cross/Ref or DOI System DOI Resolver.

The DOI System