{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://raw.githubusercontent.com/api-evangelist/pubmed/main/json-schema/pubmed-article.json",
  "title": "PubMed Article",
  "description": "Schema for a PubMed article citation including metadata, abstract, authors, MeSH terms, and identifiers as returned by the NCBI E-utilities API.",
  "type": "object",
  "properties": {
    "pmid": {
      "type": "string",
      "description": "PubMed unique identifier (PMID).",
      "pattern": "^[0-9]+$",
      "example": "36328499"
    },
    "title": {
      "type": "string",
      "description": "Full article title."
    },
    "abstract": {
      "type": "string",
      "description": "Full article abstract text."
    },
    "authors": {
      "type": "array",
      "description": "List of authors.",
      "items": {
        "$ref": "#/$defs/Author"
      }
    },
    "journal": {
      "$ref": "#/$defs/Journal"
    },
    "pubDate": {
      "type": "string",
      "description": "Publication date in YYYY/MM/DD format.",
      "example": "2023/01/15"
    },
    "doi": {
      "type": "string",
      "description": "Digital Object Identifier (DOI).",
      "example": "10.1038/s41586-022-05543-x"
    },
    "pmcid": {
      "type": "string",
      "description": "PubMed Central identifier.",
      "pattern": "^PMC[0-9]+$",
      "example": "PMC9876543"
    },
    "meshTerms": {
      "type": "array",
      "description": "Medical Subject Headings (MeSH) terms assigned to the article.",
      "items": {
        "$ref": "#/$defs/MeshTerm"
      }
    },
    "keywords": {
      "type": "array",
      "description": "Author-supplied keywords.",
      "items": { "type": "string" }
    },
    "publicationTypes": {
      "type": "array",
      "description": "Types of publication (e.g., Journal Article, Review, Clinical Trial).",
      "items": { "type": "string" }
    },
    "articleIds": {
      "type": "array",
      "description": "List of article identifiers across different systems.",
      "items": {
        "$ref": "#/$defs/ArticleId"
      }
    },
    "language": {
      "type": "string",
      "description": "Language of the article.",
      "example": "eng"
    },
    "country": {
      "type": "string",
      "description": "Country of the publisher.",
      "example": "United States"
    },
    "fullTextLinks": {
      "type": "array",
      "description": "Links to full text versions of the article.",
      "items": {
        "$ref": "#/$defs/FullTextLink"
      }
    },
    "grantList": {
      "type": "array",
      "description": "Funding grants associated with the article.",
      "items": {
        "$ref": "#/$defs/Grant"
      }
    },
    "affiliations": {
      "type": "array",
      "description": "Author affiliation strings.",
      "items": { "type": "string" }
    },
    "citations": {
      "type": "integer",
      "description": "Number of times the article has been cited.",
      "minimum": 0
    },
    "nlmUniqueId": {
      "type": "string",
      "description": "NLM unique identifier for the journal."
    },
    "issnLinking": {
      "type": "string",
      "description": "ISSN used for linking."
    },
    "epubDate": {
      "type": "string",
      "description": "Electronic publication date."
    },
    "revisedDate": {
      "type": "string",
      "description": "Date the record was last revised."
    },
    "entrezDate": {
      "type": "string",
      "description": "Date the record entered Entrez."
    }
  },
  "required": ["pmid", "title"],
  "$defs": {
    "Author": {
      "type": "object",
      "description": "An author of the article.",
      "properties": {
        "lastName": { "type": "string", "description": "Author last name." },
        "firstName": { "type": "string", "description": "Author first name." },
        "initials": { "type": "string", "description": "Author initials." },
        "collectiveName": { "type": "string", "description": "Collective or group author name." },
        "affiliation": { "type": "string", "description": "Author institutional affiliation." },
        "orcid": {
          "type": "string",
          "description": "ORCID identifier for the author.",
          "pattern": "^[0-9]{4}-[0-9]{4}-[0-9]{4}-[0-9]{3}[0-9X]$"
        }
      }
    },
    "Journal": {
      "type": "object",
      "description": "Journal in which the article was published.",
      "properties": {
        "title": { "type": "string", "description": "Full journal title." },
        "isoAbbreviation": { "type": "string", "description": "ISO abbreviated journal title." },
        "issn": { "type": "string", "description": "ISSN of the journal." },
        "volume": { "type": "string", "description": "Volume number." },
        "issue": { "type": "string", "description": "Issue number." },
        "pages": { "type": "string", "description": "Page range.", "example": "123-134" }
      }
    },
    "MeshTerm": {
      "type": "object",
      "description": "A Medical Subject Heading (MeSH) descriptor assigned to the article.",
      "properties": {
        "descriptorName": { "type": "string", "description": "MeSH descriptor name." },
        "descriptorUI": { "type": "string", "description": "MeSH descriptor unique identifier." },
        "isMajorTopic": { "type": "boolean", "description": "Whether this is a major topic of the article." },
        "qualifierList": {
          "type": "array",
          "description": "MeSH subheading qualifiers.",
          "items": {
            "type": "object",
            "properties": {
              "qualifierName": { "type": "string" },
              "qualifierUI": { "type": "string" },
              "isMajorTopic": { "type": "boolean" }
            }
          }
        }
      }
    },
    "ArticleId": {
      "type": "object",
      "description": "An identifier for an article in a specific system.",
      "properties": {
        "idType": {
          "type": "string",
          "description": "Type of identifier.",
          "enum": ["pubmed", "pmc", "doi", "pii", "pmcbook", "bookaccession", "mid"]
        },
        "value": { "type": "string", "description": "Identifier value." }
      },
      "required": ["idType", "value"]
    },
    "FullTextLink": {
      "type": "object",
      "description": "A link to a full-text version of the article.",
      "properties": {
        "url": { "type": "string", "format": "uri", "description": "URL to the full text." },
        "name": { "type": "string", "description": "Name of the full-text provider." },
        "category": { "type": "string", "description": "Category (e.g., Free full text, Full text)." }
      }
    },
    "Grant": {
      "type": "object",
      "description": "A funding grant associated with the article.",
      "properties": {
        "grantId": { "type": "string", "description": "Grant identifier." },
        "agency": { "type": "string", "description": "Funding agency name." },
        "country": { "type": "string", "description": "Country of the funding agency." },
        "acronym": { "type": "string", "description": "Agency acronym (e.g., NIH, NHGRI)." }
      }
    }
  }
}