Adding Sources to Your Zotero Library:
Adding Citations by Identifier (ISBN, DOI, or PMID)
Zotero also allows you to add references by Identifiers, specifically ISBNs (International Standard Book Numbers), DOIs (Digital Object Identifiers) or PMIDs (PubMed Identifiers). This feature is especially useful for adding non-internet-based sources such as books without having to look them up online.
Click the Add Item by Identifier button.
Enter the identifier code.
Zotero will then look up the bibliographic information for the source and add it to the library.