Q. What is a DOI?
A DOI (Digital Object Identifier) is a unique identifier for digital objects that is more permanent than a URL. The DOI assigned never changes. Journal publishers assign DOIs to electronic copies of individual articles in journals they publish. Because the DOI insures you can find the article, citation styles like APA require the DOI in a citation for an electronic journal article.
If you don't know the DOI for an article you can look:
- On the first few pages of the article along with other citation information
- CrossRef DOI search
- The library database where you retrieved the article may have a DOI
Not all articles have DOIs, for example if it was published before 1998 (even into the early 2000s) or only published in print.