District of Columbia Code Division VIII. General Laws. § 47-2024. Additional powers.

(2) To request information from the Internal Revenue Service of the Treasury Department of the United States relative to any person for the purpose of assessing taxes imposed by this chapter; and said Internal Revenue Service is authorized and required to supply such information as may be requested by the Mayor relative to any person for the purpose herein provided;

(3) To prescribe methods for determining the gross proceeds from sales made or services rendered and for the allocation of such sales into taxable and nontaxable sales;

(4) To require any vendor selling to persons within the District to keep detailed records of the nature and value of personal property sold for use within the District, and to furnish such information upon request to the Mayor;

(5) To assess, determine, revise, and readjust the taxes imposed under this chapter; and

(6) To revoke, for reasonable cause, any registration certificate issued under the provisions of this chapter.