| Publication | Date of Publication | Type |
|---|
| Spectral Theory of the Klein–Gordon Equation in Krein Spaces | 2008-10-24 | Paper |
| Spectral theory of the Klein-Gordon equation in Pontryagin spaces | 2007-02-13 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4218801 | 2002-11-07 | Paper |
| A variational principle for eigenvalues of pencils of Hermitian matrices | 2001-11-04 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4493617 | 2001-06-28 | Paper |
| Elliptic eigenvalue problems with eigenparameter dependent boundary conditions | 2001-01-01 | Paper |
| Convergence estimate for second order Cauchy problems with a small parameter | 2000-11-13 | Paper |
| Quadratic Eigenvalue Problems | 2000-01-25 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4218788 | 1999-09-30 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4218790 | 1999-09-30 | Paper |
| The Asymptotic Behavior of the Eigenvalues of a Singularly Perturbed Linear Pencil | 1999-05-18 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4380677 | 1998-04-05 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4869257 | 1998-03-23 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4380674 | 1998-03-17 | Paper |
| Instability of singular critical points of definitizable operators | 1998-02-05 | Paper |
| Preservation of the range under perturbations of an operator | 1997-12-11 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4869256 | 1997-10-20 | Paper |
| Resolvent Estimates for Singularly Perturbed Elliptic Operators in Hölder Spaces | 1997-08-25 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4718327 | 1997-01-07 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4276441 | 1996-04-01 | Paper |
| Quasilinear parabolic-parabolic singular perturbations | 1996-01-22 | Paper |
| The Operator (sgn x) d 2 dx 2 is Similar to a Selfadjoint Operator in L 2 ( R ) | 1995-08-21 | Paper |
| A Krein space approach to elliptic eigenvalue problems with indefinite weights | 1995-06-25 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4327366 | 1995-04-05 | Paper |
| A Variational Principle in Krein Space | 1995-01-09 | Paper |
| A minimax characterization for eigenvalues of Hermitian pencils. II | 1994-05-12 | Paper |
| Leading coefficients of the eigenvalues of perturbed analytic matrix functions | 1993-08-17 | Paper |
| Time singular limit of semilinear wave equations with damping | 1993-08-16 | Paper |
| Remarks on the perturbation of analytic matrix functions. III | 1993-06-29 | Paper |
| Perturbation of the Eigenvalues of Quadratic Matrix Polynomials | 1992-09-27 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4011388 | 1992-09-27 | Paper |
| The nonrelativistic limit of the nonlinear Dirac equation | 1992-06-28 | Paper |
| A minimax characterization for eigenvalues of Hermitian pencils | 1991-01-01 | Paper |
| Convexity Properties of Distinguished Eigenvalues of Certain Classes of Operators | 1991-01-01 | Paper |
| The nonrelativistic limit of the nonlinear Klein-Gordon equation | 1990-01-01 | Paper |
| Remarks on the perturbation of analytic matrix functions. II | 1989-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3031103 | 1989-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3202517 | 1989-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3492161 | 1989-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4204485 | 1989-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3482163 | 1988-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3779241 | 1987-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3803488 | 1987-01-01 | Paper |
| Remarks on the perturbation of analytic matrix functions | 1986-01-01 | Paper |
| Some interlacing results for indefinite Hermitian matrices | 1985-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3681240 | 1984-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3692109 | 1984-01-01 | Paper |
| Eigenvalues of the Klein-Gordon equation | 1983-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3310439 | 1983-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3663899 | 1983-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4743146 | 1983-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3312625 | 1982-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3658605 | 1982-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4741250 | 1982-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3927723 | 1981-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3940346 | 1981-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3879781 | 1980-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3879799 | 1980-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3892799 | 1980-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3900534 | 1980-01-01 | Paper |
| Localization of the critical points of Klein-Gordon type operators | 1980-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q3866677 | 1979-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4186887 | 1979-01-01 | Paper |
| https://portal.mardi4nfdi.de/entity/Q4094011 | 1976-01-01 | Paper |
