Inversion in the unit sphere for powers of the Laplacian -- Nonlinear second order boundary value problems: An existence-uniqueness theorem of S. N. Bernstein -- A definiteness result for determinantal operators -- On second-order left-definite boundary value problems -- A von Neumann factorization of some selfadjoint extensions of positive symmetric differential operators and its application to inequalities -- Inclusion theorems for solutions of differential equations with aid of pointwise or vector monotonicity -- The liouville-green asymptotic theory for second-order differential equations: A new approach and some extensions -- Non-self-adjoint operators and their essential spectra -- A concept of adjointness and symmetry of differential expressions based on the generalised Lagrange identity and Green's formula -- On quadratic integral inequalities associated with second-order symmetric differential expressions -- Nonoscillation theorems for differential equations with general deviating arguments -- Self-adjoint 4-th order boundary value problem in the limit - 4 case -- Factorization and the Friedrichs extension for ordinary differential operators -- Eigenvalue problems and the Riemann zeta function II -- Boundedness criteria for hyperbolic characteristic initial value problems -- Matrix riccati inequality and oscillation of second order differential systems -- A new approach to second order linear oscillation theory -- Small amplitude limit cycles of polynomial differential equations -- Regular growth and zero-tending solutions -- Asymptotic distribution of the eigenvalues of non-definite Sturm-Liouville problems -- Some remarks on the order of an entire function associated with a second order differential equation -- Steepest descent for general systems of linear differential equations in Hilbert space -- On the spectral theory of some nonsymmetric second order differential operators -- The Cauchy and backward-Cauchy problem for a nonlinearly hyperelastic/viscoelastic infinite rod -- Floquet theory for doubly-periodic differential equations and a number theory conjecture -- Poincaré's type of equations in the study of limit cycles -- Das Gesetz von Maxwell-Clausius in der phaenomenologischen Thermodynamik.