{
    "specification": "Basic Metadata per referent sub-type, Smart Scholars DOI Registry, version 1.0 (1 October 2026)",
    "model": "DOI System Metadata (DOI Handbook 10.1; ISO 26324:2025, Annex B)",
    "document": "https://registry.smartscholars.in/system-metadata.php",
    "elements": {
        "descriptive": [
            "DOI name (1)",
            "alternateIdentifier (0-n)",
            "referentName (1-n)",
            "referentType (1)",
            "referentSubType (1)",
            "relatedIdentifiers (0-n)",
            "basicMetadata (1)"
        ],
        "administrative": [
            "registrationAuthorityCode (1)",
            "issueDate (1)"
        ]
    },
    "subTypes": {
        "JournalArticle": {
            "label": "Journal article",
            "required": [
                {
                    "id": "date",
                    "what": "the publication date (at least the year)"
                },
                {
                    "id": "journal",
                    "what": "the journal it belongs to — its title and its ISSN (or the journal's own DOI)"
                }
            ],
            "recommended": [
                {
                    "id": "creator",
                    "what": "its author(s), editor(s) or corporate author"
                },
                {
                    "id": "volume",
                    "what": "the volume number"
                },
                {
                    "id": "issue",
                    "what": "the issue number"
                },
                {
                    "id": "pages",
                    "what": "the first page or an article number"
                },
                {
                    "id": "language",
                    "what": "the language of the content"
                },
                {
                    "id": "abstract",
                    "what": "an abstract or description"
                },
                {
                    "id": "license",
                    "what": "the licence"
                },
                {
                    "id": "references",
                    "what": "the reference list"
                }
            ],
            "crossrefRequires": "article: titles, publication_date (year), doi_data; journal: full_title, ISSN or title-level DOI"
        },
        "Journal": {
            "label": "Journal (title-level DOI)",
            "required": [
                {
                    "id": "publisher",
                    "what": "the publisher"
                }
            ],
            "recommended": [
                {
                    "id": "issn",
                    "what": "its own ISSN"
                },
                {
                    "id": "language",
                    "what": "the language of the content"
                }
            ],
            "crossrefRequires": "journal: full_title, ISSN or title-level DOI and URL"
        },
        "JournalIssue": {
            "label": "Journal issue",
            "required": [
                {
                    "id": "journal",
                    "what": "the journal it belongs to — its title and its ISSN (or the journal's own DOI)"
                },
                {
                    "id": "date",
                    "what": "the publication date (at least the year)"
                },
                {
                    "id": "designation",
                    "what": "its issue or volume number"
                }
            ],
            "recommended": [
                {
                    "id": "volume",
                    "what": "the volume number"
                },
                {
                    "id": "issue",
                    "what": "the issue number"
                },
                {
                    "id": "language",
                    "what": "the language of the content"
                }
            ],
            "crossrefRequires": "issue: issue, publication_date (year)"
        },
        "JournalVolume": {
            "label": "Journal volume",
            "required": [
                {
                    "id": "journal",
                    "what": "the journal it belongs to — its title and its ISSN (or the journal's own DOI)"
                },
                {
                    "id": "date",
                    "what": "the publication date (at least the year)"
                },
                {
                    "id": "volume",
                    "what": "the volume number"
                }
            ],
            "recommended": [
                {
                    "id": "language",
                    "what": "the language of the content"
                }
            ],
            "crossrefRequires": "journal_volume with the journal's full_title and ISSN"
        },
        "Book": {
            "label": "Book",
            "required": [
                {
                    "id": "date",
                    "what": "the publication date (at least the year)"
                },
                {
                    "id": "publisher",
                    "what": "the publisher"
                }
            ],
            "recommended": [
                {
                    "id": "isbn",
                    "what": "an ISBN (its own or its book's)"
                },
                {
                    "id": "creator",
                    "what": "its author(s), editor(s) or corporate author"
                },
                {
                    "id": "language",
                    "what": "the language of the content"
                },
                {
                    "id": "license",
                    "what": "the licence"
                }
            ],
            "crossrefRequires": "book: titles, publication_date (year), publisher"
        },
        "BookChapter": {
            "label": "Book chapter",
            "required": [
                {
                    "id": "book",
                    "what": "the book it belongs to — its title"
                },
                {
                    "id": "date",
                    "what": "the publication date (at least the year)"
                }
            ],
            "recommended": [
                {
                    "id": "creator",
                    "what": "its author(s), editor(s) or corporate author"
                },
                {
                    "id": "pages",
                    "what": "the first page or an article number"
                },
                {
                    "id": "isbn",
                    "what": "an ISBN (its own or its book's)"
                }
            ],
            "crossrefRequires": "chapter: doi_data (titles, contributors, pages, publication_date recommended), inside its book"
        },
        "BookSeries": {
            "label": "Book series",
            "required": [
                {
                    "id": "issn",
                    "what": "its own ISSN"
                },
                {
                    "id": "publisher",
                    "what": "the publisher"
                }
            ],
            "recommended": [
                {
                    "id": "language",
                    "what": "the language of the content"
                }
            ],
            "crossrefRequires": "series: titles, ISSN, volume, publication_date (year), publisher"
        },
        "ConferenceProceedings": {
            "label": "Conference paper",
            "required": [
                {
                    "id": "proceedings",
                    "what": "the proceedings it belongs to — their title"
                },
                {
                    "id": "date",
                    "what": "the publication date (at least the year)"
                },
                {
                    "id": "creator",
                    "what": "its author(s), editor(s) or corporate author"
                }
            ],
            "recommended": [
                {
                    "id": "pages",
                    "what": "the first page or an article number"
                },
                {
                    "id": "abstract",
                    "what": "an abstract or description"
                },
                {
                    "id": "license",
                    "what": "the licence"
                },
                {
                    "id": "references",
                    "what": "the reference list"
                }
            ],
            "crossrefRequires": "conference paper: contributors, titles, doi_data; proceedings: proceedings_title, publisher, publication_date (year)"
        },
        "ConferenceProceedings/volume": {
            "label": "Conference proceedings (the volume)",
            "required": [
                {
                    "id": "date",
                    "what": "the publication date (at least the year)"
                },
                {
                    "id": "publisher",
                    "what": "the publisher"
                }
            ],
            "recommended": [
                {
                    "id": "isbn",
                    "what": "an ISBN (its own or its book's)"
                },
                {
                    "id": "creator",
                    "what": "its author(s), editor(s) or corporate author"
                }
            ],
            "crossrefRequires": "proceedings: proceedings_title, publisher, publication_date (year)"
        },
        "Dataset": {
            "label": "Dataset or database",
            "required": [
                {
                    "id": "date",
                    "what": "the publication date (at least the year)"
                },
                {
                    "id": "publisher",
                    "what": "the publisher"
                }
            ],
            "recommended": [
                {
                    "id": "creator",
                    "what": "its author(s), editor(s) or corporate author"
                },
                {
                    "id": "abstract",
                    "what": "an abstract or description"
                },
                {
                    "id": "license",
                    "what": "the licence"
                }
            ],
            "crossrefRequires": "database: titles; dataset: doi_data (DataCite requires creator, title, publisher, publication year, resource type)"
        },
        "Report": {
            "label": "Report",
            "required": [
                {
                    "id": "date",
                    "what": "the publication date (at least the year)"
                }
            ],
            "recommended": [
                {
                    "id": "creator",
                    "what": "its author(s), editor(s) or corporate author"
                },
                {
                    "id": "publisher",
                    "what": "the publisher"
                },
                {
                    "id": "language",
                    "what": "the language of the content"
                }
            ],
            "crossrefRequires": "report: title, publication_date (year)"
        },
        "Thesis": {
            "label": "Thesis or dissertation",
            "required": [
                {
                    "id": "date",
                    "what": "the publication date (at least the year)"
                },
                {
                    "id": "institution",
                    "what": "the institution that issued or awarded it (the publisher or corporate author, an organisation)"
                }
            ],
            "recommended": [
                {
                    "id": "creator",
                    "what": "its author(s), editor(s) or corporate author"
                },
                {
                    "id": "language",
                    "what": "the language of the content"
                }
            ],
            "crossrefRequires": "dissertation: titles, approval_date, institution, doi_data"
        },
        "Standard": {
            "label": "Standard",
            "required": [
                {
                    "id": "date",
                    "what": "the publication date (at least the year)"
                },
                {
                    "id": "publisher",
                    "what": "the publisher"
                },
                {
                    "id": "designator",
                    "what": "the standard's designation (an identifier besides the DOI)"
                }
            ],
            "recommended": [
                {
                    "id": "language",
                    "what": "the language of the content"
                }
            ],
            "crossrefRequires": "standard: title, designator, approval_date, standard_body_name, standard_body_acronym"
        },
        "Figure": {
            "label": "Figure, table or supplementary file",
            "required": [
                {
                    "id": "parent",
                    "what": "the work it is part of, by that work's DOI"
                }
            ],
            "recommended": [
                {
                    "id": "date",
                    "what": "the publication date (at least the year)"
                }
            ],
            "crossrefRequires": "component: doi_data, under its parent work"
        },
        "WebResource": {
            "label": "Web resource or posted content",
            "required": [
                {
                    "id": "date",
                    "what": "the publication date (at least the year)"
                }
            ],
            "recommended": [
                {
                    "id": "creator",
                    "what": "its author(s), editor(s) or corporate author"
                },
                {
                    "id": "publisher",
                    "what": "the publisher"
                },
                {
                    "id": "abstract",
                    "what": "an abstract or description"
                }
            ],
            "crossrefRequires": "posted content: titles, posted_date, doi_data"
        }
    }
}