Disconjugacy (Lecture Notes in Mathematics, 220)
Theory of a Higher-Order Sturm-Liouville Equation (Lecture Notes in Mathematics, 1659)
Spectral Theory of Ordinary Differential Operators (Lecture Notes in Mathematics, 1258)
Discontinuous Cebysev Systems (Lecture Notes in Mathematics, 707)
Hilbert Space, Boundary Value Problems, and Orthogonal Polynomials
Almost Periodic Differential Equations (Lecture Notes in Mathematics, 377)
Bessel Polynomials (Lecture Notes in Mathematics, 698)
Non-Oscillation Domains of Differential Equations with Two Parameters (Lecture Notes in Mathematics, 1338)
Precise Spectral Asymptotics for Elliptic Operators Acting in Fiberings over Manifolds with Boundary (Lecture Notes in Mathematics, 1100)
Differential Equations with Operator Coefficients with Applications to Boundary Value Problems for Partial Differential Equations