1. Stability of a minimization problem under perturbation of the set of admissible elements;Berdyshev;Mat. Sb.,1977
2. Representers of linear functionals, norm- attaining functionals and best approximation by cones and linear varieties in inner product spaces;Deutsch;J. Approx. Theory,1982
3. Smoothness and Renormings in Banach Spaces;Deville,1993
4. Banach spaces with strongly subdifferentiable norm;Franchetti;Boll. Uni. Mat. Ital.,1993
5. On the best approximation by elements of infinite dimensional subspaces of a certain class;Garkavi;Mat. Sb.,1963