Whenever in the opinion of the commissioner it is necessary to examine any copy of the federal income tax returns of any taxpayer in order to audit properly the state returns of the taxpayer, the commissioner shall have the right to examine the federal returns and all statements, inventories, and schedules in support of the returns.
(Ga. L. 1931, Ex. Sess., p. 24, § 47; Ga. L. 1931, p. 7, § 85; Code 1933, § 92-3215; Code 1933, § 91A-3710, enacted by Ga. L. 1978, p. 309, § 2.)