Spherical Harmonics (Lecture Notes in Mathematics, 17)
Discontinuous Cebysev Systems (Lecture Notes in Mathematics, 707)
Disconjugacy (Lecture Notes in Mathematics, 220)
Lectures on Summability (Lecture Notes in Mathematics, 107)
Regular Boundary Value Problems Associated with Pairs of Ordinary Differential Expressions (Lecture Notes in Mathematics, 858)
Absolute Summability of Fourier Series and Orthogonal Series (Lecture Notes in Mathematics, 1067)
Polynomes Orthogonaux Formels - Applications (Lecture Notes in Mathematics, 974) (French Edition)
Vorlesungen über Orthogonalreihen
Extremum Problems for Bounded Univalent Functions (Lecture Notes in Mathematics, 646)
Generalized Bessel Functions of the First Kind