In my bachelor thesis (B.A., media science) I am comparing the user interfaces of iOS 5.1.1 and Windows Phone 7.5. I'm focussing on their use of "real world" things. While I know of their guidelines (WP and iOS), I was wondering if documents by these companies exist that don't tell developers how to design but justify how these mobile operating systems look.
I'd appreciate your help and am also looking for literature on the use of real world textures/sounds/metaphors in user interfaces.