Zur Spektraltheorie von Sturm-Liouville-Operatoren

Perturbation Theory for Linear Operators

1995 • 17,079 citations

Theory of Ordinary Differential Equations

1956 • 6,499 citations

Theory of ordinary differential equations

1956 • 5,705 citations

Perturbation theory for linear operators

1966 • 2,651 citations

Eigenfunction expansions associated with second-order differential equations

1946 • 1,847 citations

�ber gew�hnliche Differentialgleichungen mit Singularit�ten und die zugeh�rigen Entwicklungen willk�rlicher Funktionen

1910 • 834 citations

Linear operators. Part II. Spectral theory

2003 • 514 citations

Eigenfunction expansions associated with the Schroedinger operators and their applications to scattering theory

1960 • 355 citations

Uniqueness of the self-adjoint extension of singular elliptic differential operators

1962 • 193 citations

Lineare Differentialoperatoren

1960 • 147 citations

On a Problem of Weyl in the Theory of Singular Sturm-Liouville Equations

1957 • 125 citations

Differential equations with non-oscillatory eigenfunctions

1948 • 64 citations

An Oscillation Theorem for Continuous Spectra

1947 • 33 citations

On the discreteness of spectra of singular Sturm‐Liouville problems

1959 • 26 citations

A Characterization of the Spectra of One-Dimensional Wave Equations

1949 • 24 citations

Criteria of Non-Degeneracy for the Wave Equation

1948 • 23 citations

The Least Cluster Point of the Spectrum of Boundary Value Problems

1948 • 23 citations

A Separation Theorem for Continuous Spectra

1949 • 21 citations

Differential operators with a purely continuous spectrum

1963 • 9 citations

Perturbation by Changes One-Dimensional Boundary Conditions

1956 • 8 citations

Numbers and functions computable by means of rational recurrence formulae

1959 • 4 citations

On Perturbations of the Continuous Spectrum of the Harmonic Oscillator

1952 • 4 citations