H. Langer

• Contributions to operator theory in spaces with an indefinite metric
• Linear Operators and Matrices
• Linear operators and matrices
• Operator Theory and Boundary Eigenvalue Problems
• Operator theory and indefinite inner product spaces
• Competition Law of the United States
• Introduction to the Spectral Theory of Operators in Spaces with an Indefinite Metric
• Markov processes and control theory
• Planen und Gestalten