Answered By: Theresa Bell
Last Updated: Dec 06, 2017     Views: 565

A periodical is anything that is published on a regular, predictable schedule, such as a journal, a report from an annual conference, or a corporate annual report. For examples of many types of periodical references, please see search WriteAnswers for a specific resource type (e.g., journal article) or see pages 198-202 of the Publication Manual of the American Psychological Association (American Psychological Association, 2010).

The primary method used by the APA manual to identify the retrieval location of electronic periodical articles is the Digital Object Identifier (DOI) system. A 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” (American Psychological Association, 2010, p. 189). The DOI may “be hidden under a button labeled Article, Crossref, PubMed, or another full-text vendor name” (p. 189) when you retrieve the article from one of RRU’s electronic databases. Click on the button to see the DOI. If a DOI is available for an article, no other retrieval information is required; however, if the article hasn’t been assigned a DOI but was retrieved from a password-protected database, provide the name of the database instead of a DOI.

For more information on DOIs, please see "How to Find DOIs in APA PsycINFO" (addresses DOIs and how to find them within databases). To check if your resource has a DOI, use this search tool: To check your entire reference list for available DOIs, give this tool a try: You’ll need to sign up for that function, but it’s free. If you’re unsure whether you should be providing a DOI or URL, please see the "DOI and URL Flowchart" for help.


American Psychological Association. (2010). Publication manual of the American Psychological Association (6th ed.). Washington, DC: Author.