| Spectral theory of block operator matrices and applications C Tretter World Scientific, 2008 | 517 | 2008 |
| A Krein Space Approach to PT-symmetry H Langer, C Tretter Czechoslovak Journal of Physics 54, 1113-1120, 2004 | 157 | 2004 |
| Spectral decomposition of some nonselfadjoint block operator matrices H Langer, C Tretter Journal of Operator Theory, 339-359, 1998 | 112 | 1998 |
| A new concept for block operator matrices: the quadratic numerical range H Langer, A Markus, V Matsaev, C Tretter Linear algebra and its applications 330 (1-3), 89-112, 2001 | 111 | 2001 |
| Boundary eigenvalue problems for differential equations Nη= λPη with λ-polynomial boundary conditions C Tretter Journal of Differential Equations 170 (2), 408-471, 2001 | 91 | 2001 |
| Spectral inclusion for unbounded block operator matrices C Tretter Journal of Functional Analysis 256 (11), 3806-3829, 2009 | 67 | 2009 |
| Spectral Analysis for Linear Pencils N — λP of Ordinary Differential Operators AA Shkalikov, C Tretter Mathematische Nachrichten 179 (1), 275-305, 1996 | 63 | 1996 |
| Existence and uniqueness of contractive solutions of some Riccati equations V Adamjan, H Langer, C Tretter Journal of Functional Analysis 179 (2), 448-473, 2001 | 62 | 2001 |
| Eigenvalue estimates for non-selfadjoint Dirac operators on the real line JC Cuenin, A Laptev, C Tretter Annales Henri Poincaré 15, 707-736, 2014 | 53 | 2014 |
| On λ-nonlinear boundary eigenvalue problems C Tretter (No Title), 1993 | 53 | 1993 |
| The Block Numerical Range of an n × n Block Operator Matrix C Tretter, M Wagenhofer SIAM journal on matrix analysis and applications 24 (4), 1003-1017, 2003 | 50 | 2003 |
| Diagonalization of certain block operator matrices and applications to Dirac operators H Langer, C Tretter Operator Theory and Analysis: The MA Kaashoek Anniversary Volume Workshop in …, 2001 | 47 | 2001 |
| Spectral Problems for Systems of Differential Equations y′ + A0y = λA1y with λ–Polynomial Boundary Conditions C Tretter Mathematische Nachrichten 214 (1), 129-172, 2000 | 46 | 2000 |
| Singular Dirac systems and Sturm–Liouville problems nonlinear in the spectral parameter H Schmid, C Tretter Journal of Differential Equations 181 (2), 511-542, 2002 | 41 | 2002 |
| Non-symmetric perturbations of self-adjoint operators JC Cuenin, C Tretter Journal of mathematical analysis and applications 441 (1), 235-258, 2016 | 39 | 2016 |
| Linear operator pencilsA-λB with discrete spectrum C Tretter Integral Equations and Operator Theory 37, 357-373, 2000 | 39 | 2000 |
| Dirichlet–Neumann inverse spectral problem for a star graph of Stieltjes strings V Pivovarchik, N Rozhenko, C Tretter Linear Algebra and its Applications 439 (8), 2263-2292, 2013 | 37 | 2013 |
| Spectral theory of the Klein–Gordon equation in Pontryagin spaces H Langer, B Najman, C Tretter Communications in mathematical physics 267 (1), 159-180, 2006 | 37 | 2006 |
| Variational principles and eigenvalue estimates for unbounded block operator matrices and applications M Kraus, M Langer, C Tretter Journal of computational and applied mathematics 171 (1-2), 311-334, 2004 | 37 | 2004 |
| Spectral theory of the Klein–Gordon equation in Krein spaces H Langer, B Najman, C Tretter Proceedings of the Edinburgh Mathematical Society 51 (3), 711-750, 2008 | 33 | 2008 |
