DOI

A DOI, or Digital Object Identifier, is a permanent alphanumeric string assigned to a published work — an article, dataset, thesis or book chapter. Unlike a URL, which breaks when a site is reorganised, a DOI resolves to the current location of the item indefinitely.

Format it as a full link (https://doi.org/10.xxxx/yyyy) in reference lists. APA 7th edition and most current styles require the DOI wherever one exists, and including it lets readers and reviewers reach the source in one click rather than searching for it.

The prefix identifies the registering publisher and the suffix identifies the specific item. When you cannot find a DOI, Crossref's metadata search will usually locate one from the title and authors, and most reference managers retrieve it automatically. Some journals also assign DOIs to datasets and supplementary materials so they can be cited independently.