O.C.G.A. § 48-7-28: Reciprocity.

A resident individual who has an established business in another state, has investment in property having a taxable situs in another state, or engages in employment in another state may deduct from the tax due upon the entire net income of the resident individual the tax paid upon the net income of the business, investment, or employment in another state when the business, investment, or employment is in a state that levies a tax upon net income. In no case shall the credit permitted under this Code section exceed the tax which would be payable to this state upon a like amount of taxable income.