A DOI (digital object identifier) is a unique alphanumeric string that identifies a specific article and provides a persistent link to its location on the Internet.
When DOIs are available include them in your citation. DOIs can be available for both print and electronic sources. The DOI is typically located on the first page of the journal article, near the copyright notice or in the bibliographic record in the database.
Extensive listing of medical journal articles compiled by the U.S. government.
