Article 9 mandates that taxpayers must maintain comprehensive accounting records detailing all income, deductions, and items affecting their income tax for a taxable period. The tax declaration must be filed based on these records, ensuring they are correct and fairly reflect income. A declaration certified by an approved, internationally recognised chartered accountant shall be accepted as correct unless the Director establishes proof to the contrary. The Director annually publishes a list of approved accounting firms. In the absence of such certification, the Director may accept the declaration or adjust it based on established facts, but any tax increase requires taxpayer agreement, court adjudication, or arbitration per Article 13.