DOI: What is it?
According to CrossRef (2002), a DOI (digital object identifier) is a "unique alphanumeric string assigned to a digital object, such as an electronic journal, article, report, or thesis. Each DOI name is unique and serves as a stable, persistent link to the full-text of an electronic item on the Internet. Unlike a URL, a DOI name doesn't change over time; even if the item moves to a new location, the DOI name stays the same." (p. 1)
All DOI numbers begin with 10 and contain a prefix and a suffix. The prefix contains four or more numbers and is assigned to organizations. The suffix is assigned by the publisher and is designed to be flexible. The prefix and suffix are separated by a slash.
The 6th Edition of the Publication Manual of the American Psychological Association recommends that the DOI should be included in the bibliography for print and electronic sources when available. The DOI should be included using the format doi:xxxxxx in the bibliography. When a DOI is not available for electronic journal articles, include the persistent URL.
DOI: Where do I find it?
The location of the DOI can depend on many things. Here are some places to look for the DOI:
- First page of the electronic journal article
- Near the copyright notice
- Database landing page for an article
- Hidden behind a button
- In the citation generated by the database
- Online using the free DOI lookup
Not every electronic journal article has a DOI. If no DOI is available and you retrieved the journal article online, you should include the persistent URL. For instructions on creating a persistent URL, check out our Making a Persistent URL guide.