Pub. L. 91-106, tit. VI, sec. 607

Sec. 607. Nothing in the amendments made by this title shall be construed to have the effect— (1) of increasing or decreasing the amount of District of Columbia income or franchise tax determined for any taxable year beginning before January 1, 1969, or (2) of authorizing or requiring in the determination of District of Columbia income or franchise tax for any taxable year beginning after December 31, 1968, the inclusion in gross income of any gain, or the deduction from gross income of any loss, from the sale or other disposition in a taxable year beginning before January 1, 1969, of any property.