The similarity problem for J-nonnegative Sturm–Liouville operators IM Karabash, AS Kostenko, MM Malamud Journal of Differential Equations 246 (3), 964-997, 2009 | 47 | 2009 |

Indefinite Sturm-Liouville operators (sgn x)(− d2 dx2+ q) with finite-zone potentials IM Karabash, MM Malamud Operators and Matrices 1 (3), 301-368, 2007 | 46 | 2007 |

Bohl–Perron-type stability theorems for linear difference equations with infinite delay E Braverman, IM Karabash Journal of Difference Equations and Applications 18 (5), 909-939, 2012 | 35 | 2012 |

Spectral properties of singular Sturm-Liouville operators with indefinite weight sgn x I Karabash, C Trunk Proc. Roy. Soc. Edinburgh Sect. A 139, 483-503, 2009 | 32 | 2009 |

Abstract kinetic equations with positive collision operators IM Karabash Spectral Theory in Inner Product Spaces and Applications, 175-195, 2008 | 27 | 2008 |

J-selfadjoint ordinary differential operators similar to selfadjoint operators IM Karabash Methods of Functional Analysis and Topology 6 (2), 22-49, 2000 | 27 | 2000 |

Indefinite Sturm–Liouville operators with the singular critical point zero I Karabash, A Kostenko Proceedings of the Royal Society of Edinburgh: Section A Mathematics 138 (04 …, 2008 | 21 | 2008 |

The similarity of a J-self-adjoint Sturm-Liouville operator with finite-gap potential to a self-adjoint operator IM Karabash, MM Malamud Doklady. Mathematics 69 (2), 195-199, 2004 | 21 | 2004 |

On the nature of ill-posedness of the forward-backward heat equation M Chugunova, IM Karabash, SG Pyatkov Integral Equations and Operator Theory 65 (3), 319-344, 2009 | 19 | 2009 |

Optimization of quasi-normal eigenvalues for 1-D wave equations in inhomogeneous media; description of optimal structures IM Karabash Asymptotic Analysis 81 (3), 273-295, 2013 | 15 | 2013 |

Pareto optimal structures producing resonances of minimal decay under L1-type constraints IM Karabash Journal of Differential Equations 257 (2), 374-414, 2014 | 10 | 2014 |

On similarity of the operators type sgn x“− d2 dx2+ cδ” to a normal or to a selfadjoint one IM Karabash, AS Kostenko Math. Notes 74 (1), 134-139, 2003 | 10 | 2003 |

Resonance free regions and non-Hermitian spectral optimization for Schr\" odinger point interactions S Albeverio, IM Karabash arXiv preprint arXiv:1708.01334, 2017 | 9 | 2017 |

A functional model, eigenvalues, and finite singular critical points for indefinite Sturm-Liouville operators IM Karabash Oper. Theory Adv. Appl 203, 247-287, 2010 | 9 | 2010 |

On similarity of differential operators to selfadjoint ones IM Karabash Candidate thesis, The Institute of Applied Mathemtics and Mechanics NASU …, 2005 | 9 | 2005 |

Similarity of Type Operators to Normal and Self-adjoint Operators IM Karabash, AS Kostenko Mathematical Notes 74 (1), 127-131, 2003 | 9* | 2003 |

On the similarity of a J-nonnegative Sturm-Liouville operator to a self-adjoint operator IM Karabash, AS Kostenko Functional Analysis and Its Applications 43 (1), 65-68, 2009 | 8 | 2009 |

On J-self-adjoint differential operators similar to self-adjoint operators IM Karabash Mathematical Notes 68 (5), 798-799, 2000 | 8 | 2000 |

Nonlinear Bang–Bang Eigenproblems and Optimization of Resonances in Layered Cavities IM Karabash, OM Logachova, IV Verbytskyi Integral Equations and Operator Theory 88 (1), 15-44, 2017 | 7 | 2017 |

Structured stability radii and exponential stability tests for Volterra difference systems E Braverman, IM Karabash Computers & Mathematics with Applications 66 (11), 2259-2280, 2013 | 7 | 2013 |