PETRINA, D. Ya. Spectrum and states of the BCS Hamiltonian with sources. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 60, n. 9, p. 1243–1269, 2008. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3240. Acesso em: 6 dec. 2025.