A DOI (digital object identifier) is a unique alphanumeric string that identifies a specific source. Unlike URLs, DOIs are persistent and will not change. DOIs are typically used by journal articles, but some books, data sets, and government publications also have DOIs.
Examples:
Where do I find a DOI?
A DOI is often found on the first page of an article, the copyright page of a book, or in the database record. You may also be able to find DOIs by searching crossref.org.
What if I can't find a DOI?
Not all articles or sources have a DOI. If you can't find a DOI, then it is probably because it does not exist for the particular article or source.
