Every person liable for any fee or tax imposed by this chapter shall keep and preserve, for a period of five years, suitable records as may be necessary to determine the amount of any tax for which the person may be liable, which records shall include copies of all federal income tax and state tax returns and reports made by the person. All the person’s books, records, and invoices shall be open for examination at any time by the city treasurer. (Ord. 814 § 11, 1976).