Identifiers Object
==================

    The identifiers object is a child of the **book** object in the key ``identifiers``.

* **hash_id** *<string>*::

    The primary identifier for a book.

* **id** *<string>*::

    Secondary integer identifier for a book.

* **eisbn13** *<string>*::

    EISBN-13 identifier

* **eisbn10** *<string>*::

    EISBN-10 identifier

* **isbn13** *<string>*::

    ISBN-13 identifier

* **isbn10** *<string>*::

    ISBN-10 identifier

* **parent_isbn** *<string>*::

    EISBN-13 of a book for which this entry is a derivative work.

* **sku** *<string>*::

    SKU number used by some partners for internal record keeping.