{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "definitions": {
        "created": {
            "type": "string",
            "format": "date-time"
        },
        "modified": {
            "type": "string",
            "format": "date-time"
        }
    },
    "properties": {
        "created": {
            "$ref": "#/definitions/created"
        },
        "modified": {
            "$ref": "#/definitions/modified"
        }
    },
    "required": [
        "created",
        "modified"
    ]
}