What is a DOI?
A DOI is a digital object identifier for any type of digitally accessible intellectual property. It is a character string unique to the given article, paper or any digital entity. The DOI is designed to be a persistent link to the object, unlike URLs which can change. With a DOI one can locate an updated URL for the article or digital entity. Currently not every published article or digital object has a DOI.
To learn more about DOI’s and how to resolve them from the character string, visit the DOI System: http://www.doi.org/index.html or Wikipedia’s page at http://en.wikipedia.org/wiki/Digital_object_identifier