No disbursement of city funds shall be made except by check signed by the city manager and treasurer and specifying the purposes for which the disbursement is made and the fund from which it is drawn. No such check shall be issued until there is money to the credit of the fund from which it is to be paid sufficient to pay it together with all outstanding encumbrances upon the fund. No such check shall be issued until the claim to which it relates has been supported by an itemized bill, payroll, or time-sheet approved and signed by the responsible city officer who vouches for its correctness and reasonableness. The city manager shall note on each contract requiring the payment of money by the city the particular fund out of which it is to be paid. The council may by ordinance make further regulations for the safe-keeping and disbursement of the funds of the city.