Missouri constitution
Article IV: executive department
Section 28

No money shall be withdrawn from the state treasury except by warrant
drawn in accordance with an appropriation made by law, nor shall any obligation for
that payment of money be incurred unless the commissioner of administration certifies
it for payment and certifies that the expenditure is within the purpose as directed by the
general assembly of the appropriation and that there is in the appropriation an unencumbered
balance sufficient to pay it. At the time of issuance each such certification
shall be entered on the general accounting books as an encumbrance on the appropriation.
No appropriation shall confer authority to incur an obligation after the termination
of the fiscal period to which it relates, and every appropriation shall expire six months
after the end of the period for which made.