Library FAQs

A DOI (digital object identifier) is a unique string of numbers/letters that identifies content in an article/document and provides a persistent link to its internet location. While a URL may change or disappear, a DOI will not. You may see a DOI printed in a scholarly article (often on the first page) or in a database record from a library database like CINAHL. Some sources, especially older sources, may not have a DOI. 

Here are two reputable sources with relevant information and examples for dealing with DOIs in APA papers:

• The APA Style page DOIs and URLs offers the following guidance along with more detailed guidelines and information:
  • Include a DOI for all works that have a DOI, whether the work is online or print.
  • If an online work has both a DOI and a URL, include the DOI only
• Purdue OWL mentions DOIs on various pages, including:
  • Reference List: Articles in Periodicals throughout the page
  • Reference List: Electronic Sources throughout the page
  • Reference List: Books throughout the page

For more APA citation help, see the library's Citation Help: APA page or Ask a Librarian.