If it is something important, like a double-check on a QR Q/A or a post in the Books, then I walk up a flight of stairs to my bedroom to get my books. Otherwise, I, too, go from memory.
Currently:
FOTR: Book; special Tolkein-related shelf in room. Movie; Upstairs TV.
TTT: Book; in my "reading-space" in my room. Movie; Downstairs TV.
ROTK: Book; Reading-space. Movie; friend's house...darnnit!
Everything else (except Weapons and Warfare): At library....double darnnit!