Federal Rules of Evidence (2003) Article VI. Witnesses, page 3

Rule 612. Writing Used to Refresh Memory 
Except as otherwise provided in criminal proceedings by section 3500 of title 18, United States Code, if a witness uses a writing to refresh memory for the purpose of testifying, either--

(1) while testifying, or

(2) before testifying, if the court in its discretion determines it is necessary in the interests of justice,

an adverse party is entitled to have the writing produced at the hearing, to inspect it, to cross-examine the witness thereon, and to introduce in evidence those portions which relate to the testimony of the witness. If it is claimed that the writing contains matters not related to the subject matter of the testimony the court shall examine the writing in camera, excise any portions not so related, and order delivery of the remainder to the party entitled thereto. Any portion withheld over objections shall be preserved and made available to the appellate court in the event of an appeal. If a writing is not produced or delivered pursuant to order under this rule, the court shall make any order justice requires, except that in criminal cases when the prosecution elects not to comply, the order shall be one striking the testimony or, if the court in its discretion determines that the interests of justice so require, declaring a mistrial.

Rule 613. Prior Statements of Witnesses 
(a) Examining witness concerning prior statement.

In examining a witness concerning a prior statement made by the witness, whether written or not, the statement need not be shown nor its contents disclosed to the witness at that time, but on request the same shall be shown or disclosed to opposing counsel.

(b) Extrinsic evidence of prior inconsistent statement of witness.

Extrinsic evidence of a prior inconsistent statement by a witness is not admissible unless the witness is afforded an opportunity to explain or deny the same and the opposite party is afforded an opportunity to interrogate the witness thereon, or the interests of justice otherwise require. This provision does not apply to admissions of a party-opponent as defined in rule 801(d)(2) .

Rule 614. Calling and Interrogation of Witnesses by Court 
(a) Calling by court.

The court may, on its own motion or at the suggestion of a party, call witnesses, and all parties are entitled to cross-examine witnesses thus called.

(b) Interrogation by court.

The court may interrogate witnesses, whether called by itself or by a party.

(c) Objections.

Objections to the calling of witnesses by the court or to interrogation by it may be made at the time or at the next available opportunity when the jury is not present.

Rule 615. Exclusion of Witnesses 
At the request of a party the court shall order witnesses excluded so that they cannot hear the testimony of other witnesses, and it may make the order of its own motion. This rule does not authorize exclusion of (1) a party who is a natural person, or (2) an officer or employee of a party which is not a natural person designated as its representative by its attorney, or (3) a person whose presence is shown by a party to be essential to the presentation of the party's cause, or (4) a person authorized by statute to be present.