How do I find DOI's (Digital Object Identifiers) for sources I have used in my research?
Answer
The DOI System provides a means of persistent identification for managing information on digital networks (see https://www.doi.org). The DOI System is implemented through registration agencies such as CrossRef, an invaluable source for looking up DOIs. As of April 2020, CrossRef's total number of metadata records exceeded 112 million.
You can find a DOI by doing a CrossRef metadata search. You will need to provide as much bibliographic information data as you can such as the title, author, etc. Using the same search screen, you may also use a known DOI to find bibliographic information about an article.
APA Style's DOIs and URLs provides much more information about DOIs and APA formatting.
Important note: Effective March 2017, display guidelines for CrossRef DOI's have changed.