Nondifferentiable optimization via approximation -- On improving relaxation methods by modified gradient techniques -- The minimization of certain nondifferentiable sums of eigenvalues of symmetric matrices -- Using duality to solve discrete optimization problems: Theory and computational experience -- An extension of davidon methods to non differentiable problems -- Minimax solution of non-linear equations without calculating derivatives -- The use of the boxstep method in discrete optimization -- A method of conjugate subgradients for minimizing nondifferentiable functions