Refreshing memory
161.—(1)  A witness may while under examination refresh his or her memory by referring to any writing made by himself or herself at the time of the transaction concerning which he or she is questioned, or so soon afterwards that the court considers it likely that the transaction was at that time fresh in his or her memory.
(2)  The witness may also refer to any such writing made by any other person and read by the witness within the time mentioned in subsection (1), if, when the witness read it, the witness knew it to be correct.
(3)  Whenever the witness may refresh his or her memory by reference to any document, the witness may, with the permission of the court, refer to a copy of such document if the court is satisfied that there is sufficient reason for the non‑production of the original.
(4)  An expert may refresh his or her memory by reference to professional treatises.