- D. I. Borisov, D. A. Zezyulin, M. Znojil, “Bifurcations of thresholds in essential spectra of elliptic operators under localized non‐Hermitian perturbations”, Stud Appl Math, 146, № 4, 2021, 834

- D I Borisov, M Znojil, “On eigenvalues of a $ \mathscr{P\!T}$-symmetric operator in a thin layer”, Sb. Math., 208, № 2, 2017, 173

- D.I. Borisov, D.A. Zezyulin, “On Perturbation of Thresholds in Essential Spectrum under Coexistence of Virtual Level and Spectral Singularity”, Russ. J. Math. Phys., 31, № 1, 2024, 60

- Denis Borisov, Andrey Piatnitski, Elena Zhizhina, “Convolution Type Operators With Potential: Essential and Infinite Discrete Spectrum”, Math Methods in App Sciences, 2025, mma.10745
