A DOI, or Digital Object Identifier, is a unique, persistent identifier assigned to digital objects like electronic versions of journal articles. If you are creating a References page for an APA style research paper, you should include the article's DOI if it is provided in the article. The DOI is the last element of a citation, when included. See more about APA Style below.
If you found an article by searching a database, the result list will include the DOI for any articles that have one. You can also usually find the DOI at the top left corner of an article's first page (see image below).
NOTE: The DOI may contain alpha and/or numeric characters.
For more information about Digital Object Identifiers, click on the link below.