Some citation styles (such as APA) require DOI for referencing articles from electronic databases.

A Digital Object Identifier (DOI) is a unique alphanumeric string that identifies content and provide a persistent link to its location on the Internet. The publisher assigns a DOI when the article is published and made available electronically.

Where to find DOI?

• First page of the electronic journal article
• Near the copyright notice
• Database landing page for an article
• In the citation generated by the database
• Online, using the free DOI lookup on www.crossref.org

Not all articles or journals use DOIs. if you can't find a DOI you can use the persistent (or permanent, or stable) link url in your citation instead.

Please Ask Us if you need more help or contact your Subject Librarian.