Stupid question maybe, but have you turned on the Gold Brick Detector (in the Extras)?
When you need to do/get multiple things for a gold brick then there will be gold arrows pointing to all objects needed for that gold brick. The only thing they won't tell you is if you already got them or not, that's for you to find out.
--- "You are, in fact, the man." - Jifted Kid Owner of negative bolts in Ratchet and Clank: Going Commando.
I have turned on the gold detector but 3 arrows point to the center of the common room together and two others are in the dorm with the beds you have to hit before hitting the books. I have gotten those two already and appear to be unable to find the last book except for the fact that it appears to be stuck under a box ready to place on the bookshelf.
I'm only seeing the two rooms. The bedroom and the common area. Two arrows show the exact location of 2 I got in the bedroom. The last 3 are shown to be in the common area but the 3 arrows are in a triangle formation sitting on the floor of the common room.