Answered By: Lydia Dawe Last Updated: Sep 11, 2017 Views: 557
Firstly, not all journal articles have DOIs (Digital Object Identifiers), particularly older journal articles and articles from lesser-known journals. However, more and more articles are now assigned a DOI, which is an alphanumeric string of characters.
DOIs usually appear on the first page of the article itself, or they can appear on the page of the database which has the full text article linked. If you really want to know if an article has a DOI, use the CrossRef service. Register your email address with CrossRef, and thereafter you can copy and paste your reference list into the text box, and it will retrieve all the DOIs for the article if they are available.