The supplies purchased for the institutions under the control of the supervising department must be purchased so as to permit at least thirty days' time to pay therefor. The officer of the institution designated by the supervising department shall require itemized bills to be rendered by the person who furnishes supplies, in duplicate, for all purchases whether made upon contract or otherwise, which must be in the form prescribed by the office of management and budget and certified as required for other claims against the state.
N.D.C.C. § 25-01.1-26