1. Ben-Tal, A., "Second order theory of extremum problems", Proceedings of the International Symposium on External Methods and System Analysis (Fiacco, A.V., Kortanek, K., Editors), University of Texas, Austin, 1977, (to appear).
2. Cheney, E., Introduction to approximation theory, McGraw Hill, New York, 1966.
3. Gehner, K.R., "Necessary and sufficient optimality conditions for the Fritz-John problem with linear equality constraints", SIAM J.Control,12,pp. 140–149.
4. Gehner, K.R., "Characterization theorems for constrained approximation problems via optimization theory", J. Approximation Theory, 14, pp.51–76 (1975).
5. Lecture notes in Econ. and Math.Systems;I. Girsanov,1972