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APA Style 7th Edition

Digital Object Identifier

What is a DOI?

A DOI (digital object identifier) is a unique number assigned by publishers to journal articles, studies and book chapters available online.  When the DOI is included in a citation, it will be easier for a reader to locate the version of the work cited. 


How will I recognize a DOI number?

The DOI is made up of two components, a prefix and a suffix, separated by a forward slash.



Prefix      / Suffix


Where do I find a DOI number?

The DOI number for an online article will usually be found on the home page.  It may also be found  at the top or end of the full-text version of an article available in a database.  


Where is the DOI placed in a citation?

The DOI should be added to the end of the citation, as follows:

Hobbs, T. (2000).  Physicians should treat alcoholism as a disease.  In J. Torr (Ed.), Current Controversies:  

                   Alcoholism (pp. 219-223).  doi: EJ3010217217


What if the article has a different number?

Some databases use their own numbering systems for articles.  For instance, Proquest uses an ID number, and

EBSCO uses an accession number (example: AN2530410). 

These are not the same as a DOI (digital object identifier).  


If you do not find a DOI number for the article or online publication, then use the URL for the database or the web page.   See the following examples…


Mershon, D.H.  (2005, November-December).  Star Trek on the brain: Alien minds, human minds.  

          American Scientist, 86(2), 585. Retrieved from

Web site:

Lynch, T. (2007).  DS9 trials and tribble-ations review.  Retrieved from Psi Phi:

            Bradley’s Science Fiction Club Web site: