When formatting a bibliography for an assignment, you might be asked to include information in your citations about Digital Object Identifiers, or DOIs.
A Digital Object Identifier (DOI) serves two functions:
DOIs are important when creating citations, especially in APA style, as well as in Chicago style.
Here's an example. The DOI can be seen at the end of this APA style citation:
Vannini, P., & Taggart, J. (2012). Doing islandness: A non-representational approach to an island's sense of place.
If you click on the DOI link above, you'll be sent (if on campus) to the 'landing page' of the article--a page on the journal's website where you can typically find the article abstract and, possibly, links to the full text of the article. If you're off campus, you will be sent to a login page to access VIU's resources, and then to the landing page.
Not all information resources have DOIs. Many older articles don't. But this is becoming more the exception rather than the norm.
As mentioned above, referring to DOIs in your references/bibliography is a feature of APA and Chicago citation styles.
Check VIU Library's Citing Your Sources guide for more information on using APA, Chicago, or other citation styles.