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.
DOIs are intended to make information retrieval easier.
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
More sites are now using active DOIs. This used to be an inactive example from a JSTOR article.
MAKE a DOI ACTIVE
Simply add http://doi.org/ OR http://dx.doi.org/ before the DOI number to make it active.
RESOLVE a DOI
Have a DOI in the inactive format? Visit https://www.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.
These are examples of articles where a DOI is available BUT it is not provided at the article's landing page.