Gaps and bands of one dimensional periodic Schrödinger operators.
Generalized boundary value problems with abstract side conditions and their adjoints. II
Global behaviour of solution branches for some Neumann problems depending on one or several parameters.
Global properties of components of solutions of non-linear second order ordinary differential equations on the half-line
Grassmannian subvarieties arising in the spectral theory of ordinary differential operators.
Greensche Matrix und die Formel von Titchmarsh-Kodaira für singuläre S-hermitesche Eigenwertprobleme.