The modified Delaware source income of a nonresident individual means that part of such individual’s federal adjusted gross income and modifications provided for under § 1106 of this title derived from sources within this State determined under § 1124 of this title.
30 Del. C. 1953, § 1122; 57 Del. Laws, c. 737, § 1; 68 Del. Laws, c. 82, § 3.