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Citing sources according to APA guidelines

APA Style @ TiU

3.4 Digital Object Identifier (DOI)

What is a DOI?

A Digital Object Identifier, commonly shortened to DOI, is a unique alphanumeric string that identifies content and provides a persistent link to its location on the web. Access to the digital object is therefore guaranteed, even when the object is transferred to another web adress. You could think of the DOI as the “digital fingerprint” of a work.

Different types of works can have a DOI, such as academic journal articles, academic magazine articles, books, chapters from edited books, conference proceedings, government reports, research reports, or data sets. Newspaper articles and non-academic magazine articles generally do not have a DOI assigned.

What do DOIs look like?

All DOIs start with the number 10 followed by a period; e.g., 10.1016/j.addbeh.2008.11.004. In APA 7th, DOIs are formatted as a URL, with “” before the alphanumeric string:

How to find the DOI of a work

  1. Look at the work. For most recently published articles, you will often find the DOI somewhere on the first page. For some books and ebooks, DOIs are printed on the copyright page.
  2. Can’t find a DOI? Check the database record to see if a DOI is listed.
  3. If there is no DOI listed, go to the CrossRef website ( Crossref is one of the agencies that assigns DOIs, with a focus on academic articles. Use the “Search Metadata” tab to search for the work. If you get no results, then the work has no DOI.

When to include a DOI or URL

Follow these guidelines:

  • List a DOI for all works that have a DOI, regardless of whether you used the online version or the print version.
  • If an online work has a URL, but not a DOI:
    • For printed works or works originating from a database: do not include a URL or database name.
    • For works without a DOI from websites (with a non-database URL): if possible, provide a URL that leads directly to the work.
  • If an online work you cited is no longer available, search for an archived version on the Internet Archive ( If there is an archived version, use the archived URL. If no archived version is available the work is unrecoverable, and therefore unusable. If necessary, find a substitute publication.

Formatting of DOIs in references

  • Copy and paste the DOI directly from your browser to avoid typo’s.
  • If your work is to be published or read online, links should be live. We assume you will submit your writing assignment digitally. Therefore, all DOIs (and URLs) in the sample references are active. In a word-processing program, preferably use the standard for links (blue font, underlined).
  • Do not add a period after the DOI; this may inactivate the DOI.
  • Do not add a line break to the hyperlink; this may inactivate the link. It is acceptable if Word automatically adds a break or moves the hyperlink to its own line.
  • When DOIs are long or complex, shortDOIs may be used. The shortDOI service provided by the International DOI Foundation allows you to create shortDOIs.

    Any shortened DOI is acceptable as long as it leads to the required location.