Section 4.705-1 - Financial and cost accounting records(a) Accounts receivable invoices, adjustments to the accounts, invoice registers, carrier freight bills, shipping orders, and other documents which detail the material or services billed on the related invoices: Retain 4 years.(b) Material, work order, or service order files, consisting of purchase requisitions or purchase orders for material or services, or orders for transfer of material or supplies: Retain 4 years.(c) Cash advance recapitulations, prepared as posting entries to accounts receivable ledgers for amounts of expense vouchers prepared for employees' travel and related expenses: Retain 4 years.(d) Paid, canceled, and voided checks, other than those issued for the payment of salary and wages: Retain 4 years.(e) Accounts payable records to support disbursements of funds for materials, equipment, supplies, and services, containing originals or copies of the following and related documents: remittance advices and statements, vendors' invoices, invoice audits and distribution slips, receiving and inspection reports or comparable certifications of receipt and inspection of material or services, and debit and credit memoranda: Retain 4 years.(f) Labor cost distribution cards or equivalent documents: Retain 2 years.(g) Petty cash records showing description of expenditures, to whom paid, name of person authorizing payment, and date, including copies of vouchers and other supporting documents: Retain 2 years.