Authentication of tangible things, writings, records, and other matters and processes

United States v. Photogrammetric Data Services, Inc., 259 F.3d 229, 245-246 (4th Cir. 2001) (upholding trial court's admission of statements of defendant's manager as employee's statements as evidence against the corporation because "[manager's]....Federal Rule of Evidence of Evidence 804(b)(3) or a comparable State rule creates a hearsay exception for a statement which was at the time of its making so far contrary to the declarant's pecuniary or proprietary interest, or so far tended to subject the declarant to civil or criminal liability, or to render invalid a claim by the declarant against another, that a reasonable person in the declarant's position would not have made the statement unless believing it to be true. A statement tending to expose the declarant to criminal liability and offered to exculpate the accused is not admissible unless corroborating circumstances clearly indicate the trustworthiness of the statement.

Fed. R. Evid. 602 advisory committee's note (("[T]he rule requiring that a witness who testifies to a fact which can be perceived by the senses must have had an opportunity to observe, and must have actually observed the fact" is a 'most pervasive manifestation' of the common law insistence upon 'the most reliable sources of information.'...A person may testify to a matter only if there is sufficient evidence to show that the person has personal knowledge of the matter.

United States v. Reyes, 362 F.3d 536, 540 (8th Cir. 2004) (upholding trial court's admission of a co-conspirator's statements as recounted by an agent which did not violate defendant's Confrontation Clause rights....If a statement is offered against a criminal defendant as the statement of the defendant's co-conspirator which was made during and in furtherance, the statement is not a "testimonial" statement for purposes of the right of confrontation guaranteed by the Sixth Amendment of the United States Constitution and the statement is therefore not subject to the constraints on admissibility imposed by that confrontation right on "testimonial" hearsay statements.