COJUHARI, P. A. On the discrete spectrum of a linear operator pencil arising in transport theory. Methods of Functional Analysis and Topology, [S. l.], v. 20, n. 1, p. 10–16, 2014. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/563. Acesso em: 16 dec. 2025.