What is a DOI and when might I use one when referencing?
Answer
A DOI is a unique alpha numeric string that provides a permanent link to the document’s location online. You can often find the DOI on the title page of the journal article.
When referencing a journal article, use the Digital Object Identifier (DOI) if the source has one – it is preferable to a URL as it never changes; because of this you do not need to include a retrieval date for a reference that has a DOI (but check the rules of the style you are using just to make sure of the conventions of the style).
Use the URL for sources that have no DOI and give the retrieval date (some styles such as APA don’t require a retrieval date, but you are advised to include one for a source that is not in a fixed, non-editable format).
CrossRef.org is a website that allows you to check whether a source has its own DOI and has a tool for locating a source that does have a DOI. You can turn a DOI into a URL by appending the DOI to http://dx.doi.org
You may also be interested in watching this short video about DOIs from Cite them Right.