distribution of eigenvalues of elliptic operators on unbounded domains.- Generalized hyperanalytic function theory.- Some spectral gap results.- A regular left- definite eigenvalue problem with eigenvalue parameter in the boundary conditions.- Some topics in nonlinear wave propagation.- An ordering of oscillation types for y(n) + py = 0.- Fundamental properties of the solutions of quasilinear differential equations of the fifth order.- Oscillation properties of weakly nonlinear differential equations.- On boundary integral equation methods in stationary electromagnetic reflection.- Norm inequalities for derivatives.- Fixed point theorems.- Automatic control of errors for invariant imbedding.- A bound for solutions of a fourth order dynamical system.- Reducibility of almost periodic linear systems.- Convergence of solutions of infinite delay differential equations with an underlying space of continuous functions.- On a system of non linear strongly coupled partial differential equations arising in biology.- Differential operators with discrete spectrum.- On spectral theory for the linear selfadjoint equation Fy = ?Gy.- Estimates for some free boundary problems.- A new proof of existence of similarity solutions.- Symmetry and bifurcation from multiple eigenvalues.- Convergence to a travelling wave in an initial-boundary value problem.- Geometric remarks on second order criteria for maxima and minima.- Variational methods and almost solvability of semilinear equations.