What is a DOI? How do I find one?
Answer
DOI stands for Digital Object Identifier, a system used to identify content online. A DOI is a unique number assigned to items, like scholarly articles, on the Web. A DOI looks like this:
doi:10.1016/S0140-6736(09)60206-3.
Some citation styles, such as APA, now require DOIs in references to electronic articles.
If you have an article citation without a DOI, you can look up the DOI at CrossRef.org. Likewise, if you have a DOI but not the citation information, you can look up the citation at DOI.org.
For example, pasting the DOI above into the search box on DOI.org, retrieves this citation information:
Mechanical supports for acute, severe ankle sprain: a pragmatic, multicentre,randomised controlled trial
The Lancet, Volume 373, Issue 9663, Pages 575-581
S. Lamb, J. Marsh, J. Hutton, R. Nakash, M. Cooke
Putting the citation information above into the CrossRef.org form, retrieves this DOI:
doi:10.1016/S0140-6736(09)60206-3
Some articles and journals do not provide DOIs--it is the publisher's preference to include or not to include a DOI. When citing an article without a DOI, check the style manual (APA, AMA, ect.) for guidance.