*691After examining the briefs and the appellate record, this three-judge panel has determined unanimously that oral argument would not be of material assistance in the determination of these appeals. See Ped.R. App.P. 34(a); Tenth Circuit R. 10(e). Appellants’ motion to transfer these cases from Calendar D to Calendar B is denied and the causes are therefore ordered submitted without oral argument.

These are appeals from orders of the district court directing enforcement of four summonses issued to third parties by the Internal Revenue Service. The taxpayers instructed the third party defendants to disregard the summonses and intervened in the suits.

The taxpayers argue first that the United States government is without authority under the constitution to bring civil actions against citizens, and that the court therefore lacks jurisdiction to enforce these IRS summonses. This argument, though creative, is frivolous.

The taxpayers’ brief also suggests that the IRS is actually achieving criminal ends in this investigation under the guise of civil processes. This contention also lacks merit. The government established a prima facie case that the issuance of these summonses was in furtherance of a valid civil tax determination purpose. The taxpayers offered no proof in contradiction. See United States v. MacKay, 608 F.2d 830, at 834 (10th Cir. 1979).

AFFIRMED.