Resolve a DOI to authoritative bibliographic metadata via Crossref. Accepts bare DOI (10.1038/nature12373) or full DOI URL (https://doi.org/10.1038/nature12373). Returns work type, title, container (journal/conference), publisher, issued/published dates, abstract, authors (with ORCID + affiliations), page range, volume/issue, ISBN + ISSN lists, canonical URL, reference + citation counts, license blocks, and subject classifications. ~160M works in Crossref. Best authoritative DOI → bibliographic resolver. Metadata is CC0.