Small Library C - Castle Grand Hall 2F (Resident Evil 4 Remake)

On a table in the north east corner of the room.

On the small octagonal table on the north side of the room.

Inside the large treasure chest behind the bookshelves on the north side of the room. You need to use the Bunch of Keys to open it, specifically the key with the crow handle.

On the table in the north west corner of the room.

Inside the Square Lock Box on the east side of the bookcases in the middle of the room. You need to use the Cubic Device to open it.