Evidence of another crime, wrong, or act is not barred by the prohibition against circumstantial use of character if such other crime, wrong, or act is offered to prove the existence of a plan or scheme.

United States v. Wallace, 848 F.2d 1464, 1473 (9th Cir. 1988) ( footnotes omitted from the following statement by the court:"Additionally, we conclude that the district court abused its discretion in admitting the heroin conviction under the criteria of Rule 609(a). In balancing the probative value...A specific act of a witness sometimes may be used to impeach a witness, but if the act to be used for impeachment is similar to an act at issue in the trial, the risk of undue prejudice may increase and the trial court may therefore have more reason to exclude the impeaching act as unduly prejudicial.

United States v. Hernandez-Rivas, 348 F.3d 595, 600 (7th Cir. 2003) (upholding trial court's admission of co-conspirator's testimony about the source of the cocaine because "conversations identifying actors within the....A statement falls within the hearsay exemption for statements of co-conspirators only if the statement was made in furtherance of the conspiracy.

Fed. R. Evid. 902(2) ("A document purporting to bear the signature in the official capacity of an officer or employee of any entity included in paragraph (1) hereof, having no seal, if a public officer having a seal and having official duties in the district or political subdivision of the officer or employee certifies under seal that...Under Federal Rule of Evidence 902 (2) and comparable State rules a domestic public document not under seal is "self-authenticating" -- sufficiently authenticated to be admissible -- when such a document is accompanied by certification under seal that (a) that the signer of the document has the official capacity that the document reflects, and (b) the signature is genuine.