Iowa Code § 468.371
When bonds have been executed as provided in this part they shall be delivered to the county treasurer and the treasurer's receipt taken for each bond. The county treasurer shall register each bond in a book provided for that purpose, which shall show the number of each bond, its date, date of sale, amount, date of maturity, and the name and address of the purchaser, and if exchanged what evidences of debt were received for each bond. The record shall at all times be open to the inspection of the owners of property within the district. The treasurer shall certify on the back of each bond as follows:
This bond duly and properly registered in my office this ................ day of ........................ (month), ............ (year).
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Treasurer of the County of
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Iowa Code § 468.371