Weyl-Titchmarsh theory for Sturm-Liouville operators with distributional potentials J Eckhardt, F Gesztesy, R Nichols, G Teschl arXiv preprint arXiv:1208.4677, 2012 | 142 | 2012 |

Inverse spectral theory for Sturm-Liouville operators with distributional potentials J Eckhardt, F Gesztesy, R Nichols, G Teschl arXiv preprint arXiv:1210.7628, 2012 | 41 | 2012 |

Supersymmetry and Schrödinger-type operators with distributional matrix-valued potentials J Eckhardt, F Gesztesy, R Nichols, G Teschl Journal of Spectral Theory 4 (4), 715-768, 2015 | 40 | 2015 |

On self-adjoint boundary conditions for singular Sturm–Liouville operators bounded from below F Gesztesy, LL Littlejohn, R Nichols Journal of Differential Equations 269 (9), 6448-6491, 2020 | 30 | 2020 |

Heat kernel bounds for elliptic partial differential operators in divergence form with Robin-type boundary conditions F Gesztesy, M Mitrea, R Nichols Journal d'Analyse Mathématique 122 (1), 229-287, 2014 | 29 | 2014 |

Boundary data maps and Krein's resolvent formula for Sturm-Liouville operators on a finite interval S Clark, F Gesztesy, R Nichols, M Zinchenko arXiv preprint arXiv:1204.3314, 2012 | 29 | 2012 |

Sturm? Liouville Operators, Their Spectral Theory, and Some Applications F Gesztesy, R Nichols, M Zinchenko American Mathematical Society, 2024 | 21 | 2024 |

Inverse spectral problems for Schrödinger-type operators with distributional matrix-valued potentials J Eckhardt, F Gesztesy, R Nichols, A Sakhnovich, G Teschl | 21 | 2015 |

Principal solutions revisited S Clark, F Gesztesy, R Nichols Stochastic and Infinite Dimensional Analysis, 85-117, 2016 | 18 | 2016 |

Simplicity of eigenvalues in Anderson-type models S Naboko, R Nichols, G Stolz Arkiv för Matematik 51 (1), 157-183, 2013 | 18 | 2013 |

The Krein–von Neumann extension revisited G Fucci, F Gesztesy, K Kirsten, LL Littlejohn, R Nichols, J Stanfill Applicable Analysis 101 (5), 1593-1616, 2022 | 16 | 2022 |

On stability of square root domains for non-self-adjoint operators under additive perturbations F Gesztesy, S Hofmann, R Nichols Mathematika 62 (1), 111-182, 2016 | 16 | 2016 |

On the global limiting absorption principle for massless Dirac operators A Carey, F Gesztesy, J Kaad, G Levitina, R Nichols, D Potapov, ... Annales Henri Poincaré 19, 1993-2019, 2018 | 13 | 2018 |

Dirichlet-to-Neumann maps, abstract Weyl–Titchmarsh M-functions, and a generalized index of unbounded meromorphic operator-valued functions J Behrndt, F Gesztesy, H Holden, R Nichols Journal of Differential Equations 261 (6), 3551-3587, 2016 | 13 | 2016 |

On factorizations of analytic operator-valued functions and eigenvalue multiplicity questions F Gesztesy, H Holden, R Nichols Integral Equations and Operator Theory 82 (1), 61-94, 2015 | 13 | 2015 |

Weak convergence of spectral shift functions for one‐dimensional Schrödinger operators F Gesztesy, R Nichols Mathematische Nachrichten 285 (14‐15), 1799-1838, 2012 | 13 | 2012 |

An abstract approach to weak convergence of spectral shift functions and applications to multi-dimensional Schrödinger operators F Gesztesy, R Nichols Journal of Spectral Theory 2 (3), 225-266, 2012 | 13 | 2012 |

The limiting absorption principle for massless Dirac operators, properties of spectral shift functions, and an application to the Witten index of non-Fredholm operators A Carey, F Gesztesy, G Levitina, R Nichols, F Sukochev, D Zanin | 12 | 2023 |

Heat kernel bounds for elliptic partial differential operators in divergence form with Robin-type boundary conditions II F Gesztesy, M Mitrea, R Nichols, E Ouhabaz Proceedings of the American Mathematical Society 143 (4), 1635-1649, 2015 | 11 | 2015 |

Double operator integral methods applied to continuity of spectral shift functions AL Carey, F Gesztesy, G Levitina, R Nichols, D Potapov, F Sukochev Journal of Spectral Theory 6 (4), 747-779, 2016 | 9 | 2016 |