Mo. Rev. Stat. § 21.240

All joint expenses shall be controlled by their concurrent vote and shall be ascertained and adjusted according to their joint rules, and a certificate shall be issued, signed by the president and countersigned by the secretary of the senate, which specifies the amount due, on what account and the fund out of which it is to be paid. On the delivery of the certificate to the commissioner of administration, a warrant shall issue as in case of other demands against the state.