s admissible. § 6184Refreshing Memory—Requirements and Procedures, 28 Fed. Prac. & Proc. Evid. § 6184 (2d ed.)(intemal citations omitted); see also Goings v. U.S., 377 F.2d 753, 759-762 (8th Cir. 1967) (trial court improperly permitted prosecutor to ask leading questions concerning contents of witness