Mo. Rev. Stat. § 144.650

Every vendor selling tangible personal property for storage, use or consumption in this state shall, immediately after the effective date of sections 144.600 to 144.745, register with the director of revenue and give the names and addresses of all agents operating in this state, the location of all distribution or sales houses or offices or other places of business in this state and other information that the director of revenue requires. Every vendor shall furnish all agents with a statement to the effect that his principal has been and is complying with the provisions of sections 144.600 to 144.745.