The order appealed from, reflecting the informed judgment of the district court, is affirmed, Swann v. Charlotte-Mecklenburg Board of Education, 402 U.S. 1, 91 S.Ct. 1267, 28 L.Ed.2d 554 (1971). The district court correctly retained jurisdiction of this proceeding. and should continue to maintain that jurisdiction for a minimum period of three years. In no event should the district court dismiss this action without notice to the plaintiffs below and a hearing providing opportunity to plaintiffs to show that deliberate action by school authorities or some other agency of the State *1349 has affected the unitary status of this system so that further intervention of the district court is required. See Swann, supra, and Calhoun v. Cook, 451 F.2d 583 (5th Cir. 1971) and the cases cited in that opinion.

I