ALCÁNTARA BODE, Julio. On the algebraic multiplicities of the eigen values of the integral. Pro Mathematica, [S. l.], v. 5, n. 9-10, p. 6–15, 1991. Disponível em: https://revistas.pucp.edu.pe/index.php/promathematica/article/view/3414. Acesso em: 24 dic. 2025.