It seems like some finer type distinctions are not possible to do, like the distinction between a book and a catalog post to a book. Perhaps is this something that has been left out accidentally, but I think the type distinction is pretty hard to make. It could be that the providers of information don't really want to do this distinction, as it will lower the traffic to the catalog posts as people would rather go stright to the book.
The distinction is somewhat similar to the difference between a thing and the metadata about that thing, but with the additional constraint that the thing is a book and possibly available as an e-book.
An example of our type map is at [[ https://www.mediawiki.org/wiki/Citoid/MediaWiki:Citoid-template-type-map.json | mw:Citoid/MediaWiki:Citoid-template-type-map.json ]], compare to [[ https://developers.facebook.com/docs/reference/opengraph | Open Graph Reference Documentation ]] and [[ http://schema.org/Book | Schema:Org: Book]], and it does not include any type for an catalog post. (As an service for those that are new to citoid, the description of the configuration can be found on [[ https://www.mediawiki.org/wiki/Citoid#Configure_Citoid_on_a_Citoid-enabled_wiki | mw:Citoid#Configure Citoid on a Citoid-enabled wiki ]].)
I've asked in the Norwegian (bokmål) community if they view this as an important distinction.