Karl-Heinz Förster & Peter Jonas 
Operator Theory in Inner Product Spaces [PDF ebook] 

Linear Operators in Almost Krein Spaces.- Generalized Resolvents of a Class of Symmetric Operators in Krein Spaces.- Block Operator Matrices, Optical Potentials, Trace Class Perturbations and Scattering.- Asymptotic Expansions of Generalized Nevanlinna Functions and their Spectral Properties.- A Necessary Aspect of the Generalized Beals Condition for the Riesz Basis Property of Indefinite Sturm-Liouville Problems.- On Reducible Nonmonic Matrix Polynomials with General and Nonnegative Coefficients.- On Exceptional Extensions Close to the Generalized Friedrichs Extension of Symmetric Operators.- On the Spectrum of the Self-adjoint Extensions of a Nonnegative Linear Relation of Defect One in a Krein Space.- Canonical Differential Equations of Hilbert-Schmidt Type.- Spectral Analysis of Differential Operators with Indefinite Weights and a Local Point Interaction.- Normal Matrices in Degenerate Indefinite Inner Product Spaces.- Symmetric Hermite-Biehler Polynomials with Defect.- A Note on Indefinite Douglas’ Lemma.- Some Basic Properties of Polynomials in a Linear Relation in Linear Spaces.