JSON API filter included resources

The question is about JSON API specification and how properly do a request (I'm using ruby on rails and the json api resources gem but that's a general question anyway, I know how to implement it, I just want to follow the rules of JSON API at: http://jsonapi.org/format/) Situation 1: - I want to get all shelves - I want to include all books that are on those shelves - The get I'm supposed to use in this case is: `www.library.com/shelves?include=books` Situation 2: I want to get all books but only books that are marked as unread The get I'm supposed to use is: `www.library.com/books?filter[unread]=true` What would be correct way of designing request for all shelves with included unread books? Can't figure this one out `www.library.com/shelves?include=books&filter[books.unread]=true` ? `www.library.com/shelves?include=unread_books` ? <- would have to specify another resource, books that are unread `www.library.com/shelves?filter[books.unread]=true` ? What's the most correct way of doing this? EDIT After speaking with my tech lead and a few other programmers, the first options is favoured the most in such cases