Q. What is a DOI?

A DOI, or Digital Object Identifier, is a string of numbers, letters, and symbols used identify an electronic source and link to it online. The DOI helps readers locate a document even if the physical location of the document changes. The DOI will never change.

To find the DOI of a document, check the first page or first several pages of the document, near the copyright notice. The DOI can also be found on the database landing page for the source. If you still can't find the DOI, you can look it up on the website CrossRef.org (use the "Search Metadata" option).

Not all electronic materials will have a DOI.