Source documents that can be used to fully reconstruct a purchase include: Three competitive vendor quotations Comparative schedule Tender Board approval Standing contracts Tradesmans requisition (four copies exist) Commitment register Assets notice Receipt voucher Sales invoice Credit notes Cash receipts Deposit slips Payment voucher Schedule of accounts Computer input readout Questions Which of the above source documents in the payment system reflect ; a) Transaction authorisation? b) Verification of receipt of goods? c) Payment for transactions? d) Processing of payments by the Central Payments Office and Central Computing Services? e) Internal control to prevent fraud?