Strata

The individual or group credited with creating the main content of a product, such as a book, film, or other creative work. The value is a free‑text string representing the name(s) of the primary creator.

The physical covering or binding style of a product, such as paperback, hardback, softcover, or other variants. It indicates how the item is wrapped or protected and can include simple text descriptors like "Yes" for items that come with an additional protective cover.