BORISOV, D. On a Quantum Waveguide with a Small PT-symmetric Perturbation. Acta Polytechnica, Prague, Czech Republic, v. 47, n. 2-3, 2007. DOI: 10.14311/938. Disponível em: https://ojs.cvut.cz/ojs/index.php/ap/article/view/938. Acesso em: 22 apr. 2025.