BORISOV, D. On a Quantum Waveguide with a Small PT-symmetric Perturbation. Acta Polytechnica, [S. l.], v. 47, n. 2-3, 2007. DOI: 10.14311/938. Disponível em: https://ojst.is.cvut.cz/ojs/index.php/ap/article/view/938.. Acesso em: 12 may. 2025.