{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "title": "Reference Type Id",
    "type": "string",
    "enum": [
        "product",
        "product-type",
        "category",
        "tax-category",
        "customer",
        "customer-group",
        "cart",
        "order",
        "channel",
        "state",
        "product-discount"
    ]
}