36 CFR § 1254.34 - What are my responsibilities when using documents?
(b) You are responsible for the proper handling of and prevention of damage to all documents delivered to you until you return them. Specific handling instructions are given in §§ 1254.36 and 1254.38.
(c) When you finish using the documents, you must return them to the research room attendant.
(d) You must not remove the reference service slip that accompanies the documents to the research room.
(e) If we ask, you must return documents up to 15 minutes before closing time.
(f) Before leaving a research room, even for a short time, you must notify the research room attendant and place all documents in their proper containers.