Refreshing memory
161.—(1)  A witness may while under examination refresh his memory by referring to any writing made by himself at the time of the transaction concerning which he is questioned, or so soon afterwards that the court considers it likely that the transaction was at that time fresh in his 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 he read it, he knew it to be correct.
(3)  Whenever the witness may refresh his memory by reference to any document, he 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 memory by reference to professional treatises.