A DOI, or Digital Object Identifier, is a unique string of numbers and letters that permanently identifies an article, or other work, and links to it on the web. In short, a DOI is a permanent or persistent identifier.
DOI FORMATS -- ACTIVE or INACTIVE
When you locate an article, the DOIs may be formatted as active or inactive.
An active DOI looks like a hyperlink.
An inactive DOI omits https//doi.org/ and often starts with 10 (especially if assigned pre-2011).
Example: DOI: 10.2307/1354482 | This example is from a JSTOR article.
MAKE a DOI ACTIVE
Simply add http://dx.doi.org/ before the DOI number to make it active.
RESOLVE a DOI
Have a DOI in the inactive format? Visit https://dx.doi.org/ and paste in the DOI number to locate the item associated with the DOI.
DOIs are NOT UNIVERSAL
Not all articles, or other information sources, have a DOI. See an example in JSTOR.
#1 Where can I locate a journal articles's DOI?
Scan the web page or source. If one is assigned, it is mostly likely near the top of the web page where you located the article or may be on the article itself.
#2 Where can I find out if the article, book chapter etc. I want to use in my bibliography has a DOI?
Use CrossRef. Select the "Search Metadata"tab and paste in the title of your article, book chapter etc.
#3 If an information source has a DOI, is it automatically considered a scholarly source?
No. Though scholarly sources, especially peer-reviewed journal articles, are likely to have a DOI, non-scholarly sources may be assigned a DOI. For example, this data set has been assigned a DOI.
#4 Should I use the active or inactive form of a DOI when I want to cite it?
It depends. Consult your citation style guide (APA, MLA, CSE etc.) to determine what the style requires. Though not all citations style want DOIs formatted in the same way, many styles seem to be moving toward using the active DOI format.