APA (7th ed.) Citation Style Guide: DOIs

Many Publishers assign a Digital Object Identifier (DOI) to journal articles and other types of documents. A DOI is a unique alpha-numeric code given to individual online works. The DOI usually appears at the top of the article or in the database record for the article and begins with https://doi.org or http://dx.doi.org or DOI:. The DOI identifies content and provides a persistent link to its internet location.

At the moment, not all publishers provide DOIs. Some library databases such as PsycINFO provide a DOI for each article. When a DOI is provided, your should provide it at the end of your APA reference. If given, the DOI takes precedence over the URL.

Some databases do not provide DOIs. If the article you are citing does not include a DOI "from most academic databases, do not include a URL or database information in the reference because these works are widely available. The reference should be the same as the reference for a print version of the work."

If there is no DOI provided, try searching CrossRef.org, a free DOI lookup. 

(Publication manual of the American Psychological Association, 7th ed., 2020, p. 299)

APA suggests that when DOIs are available, you include them for both print and electronic sources.

APA provides these guidelines for including DOIs and URLs in references:

• Include a DOI for all works that have a DOI (print and online)
• When an online work has both a URL and a DOI, include only the DOI
• For works with a URL and not a DOI, include the URL when the URL will work for readers. 

(Publication manual of the American Psychological Association, 7th ed., 2020, pp. 298-299)

"Follow these guidelines to format DOIs and URLs

• Present both DOIs and URLs as hyperlinks (i.e., beginning with "http://" or "https://").  Because a hyperlink leads readers directly to the content, it is not necessary to include the words "Retrieved from" or "Accessed from" before a DOI or URL.
• It is acceptable to use either the default display settings for hyperlinks in your word-processing program (e.g. usually blue font, underlined) or plain text that is not underlined.
• Links should be live if the work is to be published or read online.
• Follow the current recommendations of the International DOI Foundation to format DOIs in the reference list which is...https://doi.org/xxxx ...
• Do not add a period after the DOI or URL because it may interfere with link functionality.

(Publication manual of the American Psychological Association, 7th ed., 2020, pp. 299-300)