The Digital Object Identifier (DOI) may be used to cite and link to electronic documents. The DOI consists of a unique alpha-numeric character string that is assigned to a document by the publisher upon the initial electronic publication. The assigned DOI never changes, i.e., When the authors use a DOI to create links to documents on the web, the DOIs are guaranteed never to change. AREJ adopted a unique DOI number  [10.33899/rengj] obtained for each article published.