DOI and publisher metadata
Crossref and DataCite are used for DOI-based citation records, journal articles, books, datasets, and other registered scholarly objects.
Data sources
Reference Verifier checks citations across multiple metadata sources
A single source often misses valid references. Reference Verifier tries multiple open sources and treats a strong match from any reliable source as evidence.
Primary lookup sources
Scholarly search indexes
OpenAlex, CORE, OpenAIRE, Semantic Scholar, Europe PMC, and DBLP help find title-based matches when a DOI is missing or incomplete.
Special formats
arXiv, Open Library, Google Books, SAMR standards lookup, and patent lookup help cover preprints, books, standards, and patents.
Why multiple sources matter
Citation metadata is fragmented. Some papers are missing from one index but present in another; some records have partial authors or incomplete years; some Chinese standards and patents require different identifiers. Reference Verifier uses a multi-source strategy so one failed lookup does not end the check.