Singer,Ivan. Duality for Nonconvex Approximation and Optimization Textual Documents - 2006. - New York: Springer, 2006. - xviii;355p.: 09952. ISBN: 978-0-387-2894-4 Subjects--Uniform Titles: Mathematics,Worst Approximation,Reverse Convex Best Approximation. Dewey Class. No.: 515.8 SIN