Q. How do I find the DOI number for citations in my References or Works Cited?

First, DOI stands for digital object identifier which is unique number assigned to a publication such as an article or book chapter.  The number actually is a combination of digits and letters.  Since the DOI is more reliable, use!  You will have a nicer looking list of References than one with messy looking unworkable URLs. 

Locate the number either on the first page of the ejournal article (near copyright notice) or the publication record in the database. 

Use Crossref  as another place to find the number, if available. Use the "Search Site search box" and click: "Metadata" to look up your publication. Since the DOI system started in 2000, a publication older than this date may not have the number.

Check the Crossref DOI Display site for more information.