Code of Organization and Civil Procedure (Cap. 12), article 583

583. A witness may refresh his memory by referring to any writing made by himself or by another person under his directio n at the time when the fact occurred o r immediately thereafter, or a t any other time when the fact was fresh in his memory and he knew th at the same was correctly stated in the writing; but in such case, the writing must be produced and may be seen by the opposite party. Party producing witness may not impeach his credit by evidence of bad character.