The payment of interest or principal on general obligation county road bonds, or retirement of registered warrants both as to principal and interest when such warrants have been issued for a proper county road purpose, are declared to be a proper county road purpose.[ 1979 ex.s. c 30 s 4; 1963 c 4 s 36.82.080. Prior: 1943 c 82 s 5, part; 1937 c 187 s 53, part; Rem. Supp. 1943 s 6450-53, part.]