Cheremnikh E, Ivasyk H, Oleksiv I. Finding the condition of finiteness of the discrete spectrum of a nonself-adjoint friedrichs model in the case of one-dimensional perturbation. TAPR [Internet]. 2020Aug.31 [cited 2024Nov.23];4(2(54):46-9. Available from: https://journals.uran.ua/tarp/article/view/210775