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:

1. It's an article identifier. It's meant to give a recognizable identity to each online resource (e.g., a journal article).
2. It's a type of web link. In fact, it's a type of permanent link, meaning that it's not meant to change. That's different than regular web addresses, which sometimes go offline or get changed during website maintenance or web programming.
   
   In many cases, you can click on a DOI link and be sent to the article or resource itself--or the landing page of that resource.

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.