1. Accounting Standards Board, 1999. Statement of Principles (Chapter 3).
2. Do non-audit services compromise auditor independence? further evidence;Ashbaugh;The Accounting Review,2003
3. Audit Commission Act, 1998. ISBN:0-10-541898-6.
4. Audit Commission, 2002a. Who audits the auditors? LAP2617, London, England.
5. Audit Commission, 2002b. Code of Audit Practice 2002. GAP2736, Audit Commission, London, England.