Handwriting or any other matter requiring authentication may be authenticated by having an expert witness compare the disputed handwriting or other matter with an authenticated specimen or exemplar and testifying that the author or maker of the disputed handwriting or other matter and the specimen or exemplar is the same person.

Cf. United States v. Norman, 415 F.3d 466, 473-474 (5th Cir. 2005) (affirming defendant Scott's conviction because the trial court properly disallowed defendant to cross-examine testifying DEA agents using a Justice Department....If a treatise, periodical, or similar literature is shown to be reliable and authoritative on a topic, under some circumstances a statement in such literature about the topic falls within an exception to the prohibition against the admission of hearsay evidence.

Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, pin? (1993) (based partly on a reading of Federal Rule of Evidence 702, Court repudiates the former _Frye_ general acceptance test for the admissibility of scientific evidence in federal trials; trial judge to act as...The trial court must act as an independent gatekeeper. The trial court can admit expert or scientific evidence only if it finds that scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.

United States v. Hangrove, 508 F.3d 445, 448 (7th Cir. 2007) (upholding trial court's admission of the Hicks-Veal tapes which did not violate defendant's rights under the Confrontation Clause because "coconspirator....The right of confrontation guaranteed by the Confrontation Clause of the Sixth Amendment to the U.S. Constitution puts no constraints on the admissibility of nontestimonial hearsay statements; the federal constitutional right of confrontation does not apply to such statements.