26 U.S.C. § 4903 — Liability in case of business in more than one location

The payment of the special tax imposed, other than the tax imposed by section 4411, shall not exempt from an additional special tax the person carrying on a trade or business^* in any other place than that stated in the register kept in the office of the official in charge of the internal revenue district; but nothing herein contained shall require a special tax for the storage of goods, wares, or merchandise in other places than the place of business, nor, except as provided in this subtitle, for the sale by manufacturers or producers of their own goods, wares, and merchandise, at the place of production or manufacture, and at their principal office or place of business, provided no goods, wares, or merchandise shall be kept except as samples at said office or place of business.