РАСУЛОВ, Т. Structure of the numerical range of a Friedrichs model: 1D case with rank two perturbation. Центр Научных Публикаций (buxdu.uz), [S. l.], v. 6, n. 6, 2021. Disponível em: http://journal.buxdu.uz/index.php/journals_buxdu/article/view/3163. Acesso em: 10 апр. 2025.