What is a DOI? How do I find out if an article has a DOI?
DOI stands for Digital Object Identifier. It is an alphanumeric string used to identify an item and create a persistent link on the Internet. DOIs are assigned by publishers and all begin with a 10. They are frequently listed by the copyright notice on an article. If you want to look up the DOI of an article, you can do so at Crossref using the guest query form.
Please note that according to APA 6th Edition, you must include a DOI in your citation if a DOI is available.