The director of the department of administrative services shall draw warrants on the treasurer of state for all disbursements authorized by the provisions of this chapter and chapter 459 , upon itemized and verified vouchers bearing the approval of the director of the department of natural resources. [C73, 75, 77, 79, 81, §455B.8 ] C83, §455B.107 86 Acts, ch 1245, §1899 ; 2003 Acts, ch 145, §286 ; 2004 Acts, ch 1101, §62