json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "title": "Generic ADS record",
      "description": "metadata record from random source",
      "type": "object",
      "properties": {
          "authors": {
              "type": "array",
              "items": {
                  "type": "string"
              },
              "minItems": 1,
              "_uniqueItems": true
          },
          "affiliations": {
              "type": "array",
              "items": {
                  "type": "string"
              }
          },
          "title": {
              "description": "the title of the work",
              "type": "string"
          },
          "pubdate": {
              "description": "the publication date of the work",
              "type": "string"
          },
          "source": {
              "description": "the publisher of this metadata",
              "type": "string"
          },
          "keywords": {
              "type": "array",
              "items": {
                  "type": "string"
              },
              "_uniqueItems": true
          },
          "abstract": {
              "description": "summary of the work",
              "type": "string"
          },
          "references": {
              "type": "array",
              "items": {
                  "type": "string"
              },
              "_uniqueItems": true
          },
          "properties": {
              "type": "object",
              "properties": {
                  "DOI": {
                      "type": "string"
                  },
                  "PDF": {
                      "type": "string"
                  },
                  "OPEN": {
                      "type": "number"
                  },
                  "ELECTR": {
                      "type": "string"
                  }
              }
          },
          "bibcode": {
              "type": "string"
          }
      },
      "required": [
          "authors",
          "title",
          "pubdate"
      ],
      "additionalProperties": false
  }