MUMINOV, M. I.; RASULOV, T. H. The Faddeev equation and essential spectrum of a Hamiltonian in Fock space. Methods of Functional Analysis and Topology, [S. l.], v. 17, n. 1, p. 47–57, 2011. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/469. Acesso em: 16 dec. 2025.